id: P40381
gene_symbol: swi6
product_type: PROTEIN
status: DRAFT
taxon:
  id: NCBITaxon:284812
  label: Schizosaccharomyces pombe (strain 972 / ATCC 24843)
description: >-
  Swi6 is the principal HP1 (heterochromatin protein 1) ortholog of fission
  yeast and the central structural reader and effector of heterochromatin. It is
  a 328-residue protein built from an N-terminal chromodomain that binds histone
  H3 methylated at lysine 9 (H3K9me2/me3, deposited by the Clr4 methyltransferase)
  and a C-terminal chromoshadow domain that homodimerizes and forms a
  protein-protein interaction platform, the two domains connected by a basic
  disordered hinge with nucleic-acid-binding activity. Through this architecture
  Swi6 recognizes H3K9-methylated nucleosomes, oligomerizes, and undergoes a
  switch from an auto-inhibited to a spreading-competent state that compacts
  chromatin. The chromoshadow platform recruits diverse effectors to
  heterochromatin, including the cohesin subunit Psc3, the SHREC/Clr3 histone
  deacetylase machinery, the anti-silencing JmjC protein Epe1, the RNAi bridging
  factor Ers1/RDRC, the histone chaperones Asf1/HIRA and CAF-1, DBF4-dependent
  kinase (Dfp1), the mating-type switching factor Swi2, and meiotic shugoshin
  Sgo1. Swi6 mediates transcriptional and co-transcriptional gene silencing and
  the assembly, demarcation and confinement of heterochromatin at centromeres,
  telomeres, the silent mating-type cassettes, and rDNA. At centromeres it
  enriches cohesin to ensure accurate sister-chromatid cohesion, biorientation
  and chromosome segregation; at the mating-type region it is required for donor
  selection during mating-type switching; and at telomeres it contributes to
  subtelomeric heterochromatin and telomere tethering.
existing_annotations:
- term:
    id: GO:0031507
    label: heterochromatin formation
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: involved_in
  review:
    summary: >-
      Heterochromatin formation/assembly is a core biological process of Swi6,
      conserved across the HP1 family. Phylogenetic inference is corroborated by
      extensive S. pombe experimental evidence.
    action: ACCEPT
    reason: Core HP1 function, supported by phylogeny and abundant direct evidence.
    supported_by:
    - reference_id: PMID:11283354
      supporting_text: >-
        Localization of Swi6, a homolog of Drosophila HP1, to heterochomatic
        regions is dependent on H3 Lys9 methylation.
      reference_section_type: ABSTRACT
- term:
    id: GO:0003682
    label: chromatin binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: >-
      Chromatin binding is correct but generic; the informative molecular
      function is H3K9me2/3 reader activity via the chromodomain. Retained as a
      true but non-core (parent) descriptor.
    action: KEEP_AS_NON_CORE
    reason: True but superseded by the more specific H3K9me reader activity term.
    supported_by:
    - reference_id: PMID:11242054
      supporting_text: >-
        The chromo domain of HP1 is identified as its methyl-lysine-binding domain.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005721
    label: pericentric heterochromatin
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: is_active_in
  review:
    summary: >-
      Pericentric heterochromatin is a core site of Swi6 action; this is
      strongly corroborated by direct localization data (multiple IDA
      annotations below).
    action: ACCEPT
    reason: Phylogenetic call confirmed by direct localization evidence.
    supported_by:
    - reference_id: PMID:10766735
      supporting_text: >-
        Swi6 and Chp1 are confined to the flanking outer repeats and Swi6 can
        spread across at least 3 kb of extraneous chromatin in cen1.
      reference_section_type: ABSTRACT
- term:
    id: GO:0000792
    label: heterochromatin
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  qualifier: located_in
  review:
    summary: >-
      Heterochromatin localization is correct and strongly supported by direct
      IDA evidence; Swi6 is a defining component of heterochromatin. Accepted to
      remain consistent with the IDA annotations to this term.
    action: ACCEPT
    reason: Correct and core localization, corroborated by direct evidence.
    supported_by:
    - reference_id: PMID:11069763
      supporting_text: >-
        GFP-Swi6p localises to the nucleus and is concentrated at the
        heterochromatic centromeres and telomeres.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: located_in
  review:
    summary: >-
      Swi6 is a nuclear protein. Correct but generic; the heterochromatin
      subdomain terms are the informative localizations.
    action: KEEP_AS_NON_CORE
    reason: Correct broad localization, subsumed by specific nuclear terms.
    supported_by:
    - reference_id: PMID:11069763
      supporting_text: >-
        GFP-Swi6p localises to the nucleus and is concentrated at the
        heterochromatic centromeres and telomeres.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005694
    label: chromosome
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  qualifier: located_in
  review:
    summary: >-
      Chromosome localization is correct (Swi6 is chromatin-associated) but
      generic relative to the heterochromatin and chromatin terms.
    action: KEEP_AS_NON_CORE
    reason: Correct but generic.
    supported_by:
    - reference_id: PMID:7660126
      supporting_text: >-
        Swi6p localizes with these three chromosomal regions.
      reference_section_type: ABSTRACT
- term:
    id: GO:0040029
    label: epigenetic regulation of gene expression
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  qualifier: involved_in
  review:
    summary: >-
      Swi6 mediates epigenetic gene silencing through H3K9me-based
      heterochromatin. Correct but high-level; the specific silencing/
      heterochromatin formation terms are preferred.
    action: KEEP_AS_NON_CORE
    reason: Correct but generic parent of the specific silencing processes.
    supported_by:
    - reference_id: PMID:11242054
      supporting_text: >-
        This model may also explain the stable inheritance of the
        heterochromatic state.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:14625560
  qualifier: enables
  review:
    summary: >-
      Bare "protein binding" (here the interaction with the DDK kinase subunit
      Hsk1) is uninformative. The informative molecular function captured by
      this interaction is Swi6's chromatin-protein adaptor/scaffold activity
      recruiting DDK to pericentromeric heterochromatin.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF; superseded by chromatin-protein adaptor activity.
    supported_by:
    - reference_id: PMID:31000521
      supporting_text: >-
        Swi6 interacts with Dfp1, a regulatory subunit of DBF4-dependent kinase (DDK)
      reference_section_type: ABSTRACT
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:18716626
  qualifier: enables
  review:
    summary: >-
      The Swi6-Sgo1 interaction is real and biologically important (meiotic
      cohesion protection), but "protein binding" is uninformative. The function
      is chromatin-protein adaptor activity (shugoshin recruitment).
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF; the informative term is adaptor activity.
    supported_by:
    - reference_id: PMID:18716626
      supporting_text: >-
        the heterochromatin protein Swi6 associates directly with
        meiosis-specific shugoshin Sgo1, a protector of cohesin at centromeres.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:22474355
  qualifier: enables
  review:
    summary: >-
      The Swi6-Ers1 interaction bridges Swi6 to the RDRC/RNAi machinery, but
      "protein binding" is uninformative. The informative MF is chromatin-protein
      adaptor activity (also annotated separately from this reference).
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF; captured better by adaptor activity.
    supported_by:
    - reference_id: PMID:22474355
      supporting_text: >-
        Swi6 recruits RDRC to heterochromatin through Ers1, an RNAi factor intermediate.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:22990236
  qualifier: enables
  review:
    summary: >-
      Interaction with the CHD chromatin remodeler Hrp3. "Protein binding" is
      uninformative; the informative MF is chromatin-protein adaptor activity.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF.
- term:
    id: GO:0042802
    label: identical protein binding
  evidence_type: IPI
  original_reference_id: PMID:14663140
  qualifier: enables
  review:
    summary: >-
      Swi6 homodimerizes via its chromoshadow domain; this self-association is a
      core, informative property (distinct from bare protein binding) that
      underlies effector recruitment and heterochromatin spreading.
    action: ACCEPT
    reason: Homodimerization is a genuine, mechanistically central MF.
    supported_by:
    - reference_id: PMID:10801440
      supporting_text: >-
        The 1.9 A crystal structure of the Swi6 CSD is presented here. This
        reveals a novel dimeric structure
      reference_section_type: ABSTRACT
- term:
    id: GO:0042802
    label: identical protein binding
  evidence_type: IPI
  original_reference_id: PMID:18716626
  qualifier: enables
  review:
    summary: >-
      Swi6 self-association (chromoshadow-domain homodimerization). Core MF;
      duplicate of the homodimerization annotation supported elsewhere.
    action: ACCEPT
    reason: Genuine homodimerization, central to HP1 function.
    supported_by:
    - reference_id: PMID:10801440
      supporting_text: >-
        Dimerisation through the CSD of HP1-like proteins results in the
        simultaneous formation of a putative protein-protein interaction pit
      reference_section_type: ABSTRACT
- term:
    id: GO:0042802
    label: identical protein binding
  evidence_type: IPI
  original_reference_id: PMID:23485968
  qualifier: enables
  review:
    summary: >-
      Swi6 self-associates into dimers (CSD-CSD) and higher-order oligomers; a
      conformational switch on methylated nucleosomes drives the spreading-
      competent oligomeric state. Core MF.
    action: ACCEPT
    reason: Self-association/oligomerization is mechanistically central.
    supported_by:
    - reference_id: PMID:23485968
      supporting_text: >-
        the CSD can homodimerize
      reference_section_type: RESULTS
- term:
    id: GO:0031507
    label: heterochromatin formation
  evidence_type: IDA
  original_reference_id: PMID:11780129
  qualifier: involved_in
  review:
    summary: >-
      Direct evidence that Swi6 is required for heterochromatin function at
      centromeres and the mating-type region. Core process.
    action: ACCEPT
    reason: Direct experimental support for heterochromatin formation role.
    supported_by:
    - reference_id: PMID:11780129
      supporting_text: >-
        the preferential localization of cohesins at the centromeric repeats is
        dependent on Swi6, a conserved heterochromatin protein that is required
        for proper kinetochore function.
      reference_section_type: ABSTRACT
- term:
    id: GO:0140185
    label: siRNA-mediated silent mating type cassette region heterochromatin formation
  evidence_type: EXP
  original_reference_id: PMID:39747188
  qualifier: involved_in
  review:
    summary: >-
      Swi6 participates in siRNA/RNAi-based heterochromatin nucleation at the
      mating-type cassette region, where TF-driven transcription generates
      siRNAs that trigger heterochromatin assembly. Core process.
    action: ACCEPT
    reason: Experimental support for siRNA-mediated mat-region heterochromatin.
    supported_by:
    - reference_id: PMID:39747188
      supporting_text: >-
        siRNA production by this TF-mediated transcription pathway is critical
        for heterochromatin nucleation at target repeat loci.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: EXP
  original_reference_id: PMID:18761674
  qualifier: located_in
  review:
    summary: >-
      Swi6 is a nuclear protein (CAF-1 study). Correct; generic relative to the
      heterochromatin subdomain localizations.
    action: KEEP_AS_NON_CORE
    reason: Correct but generic localization.
- term:
    id: GO:0005694
    label: chromosome
  evidence_type: EXP
  original_reference_id: PMID:18761674
  qualifier: located_in
  review:
    summary: >-
      Swi6 is chromatin/chromosome-associated. Correct but generic relative to
      the heterochromatin terms.
    action: KEEP_AS_NON_CORE
    reason: Correct but generic localization.
- term:
    id: GO:0140463
    label: chromatin-protein adaptor activity
  evidence_type: IPI
  original_reference_id: PMID:11780129
  qualifier: enables
  review:
    summary: >-
      Core molecular function. Swi6 bridges H3K9-methylated chromatin to cohesin
      via direct interaction with the cohesin subunit Psc3, enriching cohesin at
      heterochromatin. This is the informative MF underlying many "protein
      binding" interactions.
    action: ACCEPT
    reason: Direct adaptor activity (Psc3/cohesin recruitment); core function.
    supported_by:
    - reference_id: PMID:11780129
      supporting_text: >-
        a cohesin subunit Psc3 interacts with Swi6 and its mouse homologue HP1.
      reference_section_type: ABSTRACT
- term:
    id: GO:0031508
    label: pericentric heterochromatin formation
  evidence_type: IMP
  original_reference_id: PMID:19443688
  qualifier: involved_in
  review:
    summary: >-
      Swi6 is required for pericentromeric heterochromatin/silencing, acting
      with associated HDAC complexes to limit Pol II occupancy. Core process.
    action: ACCEPT
    reason: Mutant phenotype supports pericentric heterochromatin formation role.
    supported_by:
    - reference_id: PMID:19443688
      supporting_text: >-
        Swi6 and Chp2 proteins and their associated HDAC complexes have
        overlapping functions in limiting Pol II occupancy across pericentromeric
        heterochromatin domains.
      reference_section_type: ABSTRACT
- term:
    id: GO:0007535
    label: donor selection
  evidence_type: IDA
  original_reference_id: PMID:29852001
  qualifier: involved_in
  review:
    summary: >-
      Swi6 is required for correct donor selection (directionality) during
      mating-type switching, cooperating with heterochromatin and Set1C to
      direct donor choice. Core process.
    action: ACCEPT
    reason: Direct evidence for Swi6 role in donor selection.
    supported_by:
    - reference_id: PMID:29852001
      supporting_text: >-
        Mating-type switching in Schizosaccharomyces pombe entails programmed
        gene conversion events regulated by DNA replication, heterochromatin,
        and the HP1-like chromodomain protein Swi6.
      reference_section_type: ABSTRACT
- term:
    id: GO:0031508
    label: pericentric heterochromatin formation
  evidence_type: IMP
  original_reference_id: PMID:19136623
  qualifier: involved_in
  review:
    summary: >-
      Swi6 recruits SHREC, Epe1 and cohesin to pericentric heterochromatin, and
      CK2 phosphorylation of Swi6 controls transcriptional gene silencing there.
      Core process (duplicate term, distinct supporting reference).
    action: ACCEPT
    reason: Supports pericentric heterochromatin/silencing role.
    supported_by:
    - reference_id: PMID:19136623
      supporting_text: >-
        a HP1 homolog Swi6 recruits SHREC, Epe1, and cohesin, which are involved
        in transcriptional gene silencing (TGS), transcriptional activation, and
        sister chromatid cohesion, respectively.
      reference_section_type: ABSTRACT
- term:
    id: GO:0031509
    label: subtelomeric heterochromatin formation
  evidence_type: IMP
  original_reference_id: PMID:25245948
  qualifier: involved_in
  review:
    summary: >-
      Swi6 contributes to telomeric/subtelomeric heterochromatin assembly (in
      this study examined via Tls1-dependent shelterin splicing). Core process.
    action: ACCEPT
    reason: Supports subtelomeric heterochromatin formation role.
    supported_by:
    - reference_id: PMID:25245948
      supporting_text: >-
        we comprehensively identified factors required for telomeric
        heterochromatin assembly, including a novel gene tls1+.
      reference_section_type: ABSTRACT
- term:
    id: GO:0140463
    label: chromatin-protein adaptor activity
  evidence_type: IDA
  original_reference_id: PMID:36951094
  qualifier: enables
  review:
    summary: >-
      Swi6 acts as an adaptor recruiting the mating-type switching factor Swi2
      to a recombination enhancer via a defined Swi6-binding site, supporting
      donor selection. Core adaptor MF.
    action: ACCEPT
    reason: Direct evidence Swi6 recruits Swi2 (adaptor activity).
    supported_by:
    - reference_id: PMID:36951094
      supporting_text: >-
        the Swi6-binding site was required for Swi2 localization at SRE2 to
        select mat2-P in M cells.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005721
    label: pericentric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:18809570
  qualifier: is_active_in
  review:
    summary: >-
      Direct localization of Swi6 to pericentric heterochromatin. Core CC
      (one of many concordant IDA annotations).
    action: ACCEPT
    reason: Direct localization evidence.
    supported_by:
    - reference_id: PMID:18809570
      supporting_text: >-
        both Swi6 and Chp2 are required for the assembly of fully repressive
        heterochromatin
      reference_section_type: ABSTRACT
- term:
    id: GO:0031934
    label: mating-type region heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:18809570
  qualifier: is_active_in
  review:
    summary: >-
      Direct localization/activity of Swi6 at mating-type region
      heterochromatin. Core CC.
    action: ACCEPT
    reason: Direct evidence for activity at mat-region heterochromatin.
    supported_by:
    - reference_id: PMID:18809570
      supporting_text: >-
        two HP1 family proteins, Swi6 and Chp2, are involved in transcriptional
        silencing at heterochromatic regions
      reference_section_type: ABSTRACT
- term:
    id: GO:0140720
    label: subtelomeric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:18809570
  qualifier: is_active_in
  review:
    summary: >-
      Direct localization/activity of Swi6 at subtelomeric heterochromatin.
      Core CC.
    action: ACCEPT
    reason: Direct evidence for activity at subtelomeric heterochromatin.
    supported_by:
    - reference_id: PMID:18809570
      supporting_text: >-
        both Swi6 and Chp2 are required for the assembly of fully repressive heterochromatin
      reference_section_type: ABSTRACT
- term:
    id: GO:0005721
    label: pericentric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:11780129
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 localizes to and acts at pericentric (centromeric repeat)
      heterochromatin, where it enriches cohesin. Core CC.
    action: ACCEPT
    reason: Direct localization at centromeric repeats.
    supported_by:
    - reference_id: PMID:11780129
      supporting_text: >-
        the preferential localization of cohesins at the centromeric repeats is
        dependent on Swi6
      reference_section_type: ABSTRACT
- term:
    id: GO:0031934
    label: mating-type region heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:11780129
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 acts at mating-type region heterochromatin (cohesin enrichment
      preserving locus integrity). Core CC.
    action: ACCEPT
    reason: Direct evidence for activity at mat-region heterochromatin.
    supported_by:
    - reference_id: PMID:11780129
      supporting_text: >-
        Cohesin is also enriched at the mating-type heterochromatic region in a
        manner that depends on Swi6
      reference_section_type: ABSTRACT
- term:
    id: GO:0030466
    label: silent mating-type cassette heterochromatin formation
  evidence_type: EXP
  original_reference_id: PMID:15292231
  qualifier: involved_in
  review:
    summary: >-
      Swi6-dependent heterochromatin assembly across the silent mating-type
      region, downstream of Atf1/Pcr1- and Clr6-mediated histone deacetylation.
      Core process.
    action: ACCEPT
    reason: Experimental support for mat-cassette heterochromatin formation.
    supported_by:
    - reference_id: PMID:15292231
      supporting_text: >-
        a stochastic Swi6 (the fission yeast HP1 homolog)-dependent mechanism
        that is not fully understood.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:11069763
  qualifier: is_active_in
  review:
    summary: >-
      Direct (GFP) evidence for nuclear localization. Correct; generic relative
      to heterochromatin subdomains.
    action: KEEP_AS_NON_CORE
    reason: Correct but generic localization.
    supported_by:
    - reference_id: PMID:11069763
      supporting_text: >-
        GFP-Swi6p localises to the nucleus and is concentrated at the
        heterochromatic centromeres and telomeres.
      reference_section_type: ABSTRACT
- term:
    id: GO:0140463
    label: chromatin-protein adaptor activity
  evidence_type: IDA
  original_reference_id: PMID:22474355
  qualifier: enables
  review:
    summary: >-
      Swi6 functions as an adaptor recruiting the RDRC/RNAi machinery to
      heterochromatin through Ers1. Core adaptor MF (duplicate term, distinct
      reference).
    action: ACCEPT
    reason: Direct evidence Swi6 recruits RDRC via Ers1.
    supported_by:
    - reference_id: PMID:22474355
      supporting_text: >-
        we demonstrate that Swi6 recruits RDRC to heterochromatin through Ers1,
        an RNAi factor intermediate.
      reference_section_type: ABSTRACT
- term:
    id: GO:0062072
    label: histone H3K9me2/3 reader activity
  evidence_type: IDA
  original_reference_id: PMID:11242054
  qualifier: enables
  review:
    summary: >-
      Defining, core molecular function. The Swi6/HP1 chromodomain binds H3
      methylated at Lys9 (not Lys4) with high affinity; a chromodomain point
      mutation abolishes methyl-lysine binding and silencing.
    action: ACCEPT
    reason: Foundational direct demonstration of H3K9me reader activity.
    supported_by:
    - reference_id: PMID:11242054
      supporting_text: >-
        HP1 can bind with high affinity to histone H3 methylated at lysine 9 but
        not at lysine 4. The chromo domain of HP1 is identified as its
        methyl-lysine-binding domain.
      reference_section_type: ABSTRACT
- term:
    id: GO:0030466
    label: silent mating-type cassette heterochromatin formation
  evidence_type: EXP
  original_reference_id: PMID:16246721
  qualifier: involved_in
  review:
    summary: >-
      Swi6/HP1 is among the heterochromatin proteins required as Clr3 spreads
      across the ~20 kb silenced mating-type domain. Core process (duplicate
      term, distinct reference).
    action: ACCEPT
    reason: Experimental support for mat-cassette heterochromatin assembly.
    supported_by:
    - reference_id: PMID:16246721
      supporting_text: >-
        Clr3 spreads across the 20 kb silenced domain that requires its own HDAC
        activity and heterochromatin proteins including Swi6/HP1.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005721
    label: pericentric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:15372076
  qualifier: is_active_in
  review:
    summary: >-
      Direct localization of Swi6 to pericentric/centromeric heterochromatin
      (Chp1 study). Core CC.
    action: ACCEPT
    reason: Direct localization evidence.
    supported_by:
    - reference_id: PMID:15372076
      supporting_text: >-
        deletion of the chp1(+) gene causes centromere-specific decreases in
        Swi6 localization and histone H3-K9 methylation
      reference_section_type: ABSTRACT
- term:
    id: GO:0031934
    label: mating-type region heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:15372076
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 is a structural component of mating-type region heterochromatin,
      contributing to residual H3K9 methylation there. Core CC.
    action: ACCEPT
    reason: Direct evidence for activity at mat-region heterochromatin.
    supported_by:
    - reference_id: PMID:15372076
      supporting_text: >-
        Swi6 and Chp2 are critical to maintaining this residual methylation.
      reference_section_type: ABSTRACT
- term:
    id: GO:0140720
    label: subtelomeric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:15372076
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 is a structural component of telomeric/subtelomeric heterochromatin.
      Core CC.
    action: ACCEPT
    reason: Direct evidence for activity at subtelomeric heterochromatin.
    supported_by:
    - reference_id: PMID:15372076
      supporting_text: >-
        Chp1 is a structural component of three heterochromatic
        regions-centromeres, the mating-type region, and telomeres
      reference_section_type: ABSTRACT
- term:
    id: GO:0033562
    label: co-transcriptional gene silencing by RNA interference machinery
  evidence_type: IMP
  original_reference_id: PMID:17512405
  qualifier: involved_in
  review:
    summary: >-
      Swi6 contributes to RNAi-dependent heterochromatic gene silencing, which
      involves co-transcriptional RNA processing/turnover of heterochromatic
      transcripts. Core process.
    action: ACCEPT
    reason: Supports RNAi co-transcriptional silencing role.
    supported_by:
    - reference_id: PMID:17512405
      supporting_text: >-
        the RNAi pathway is required for heterochromatin-dependent silencing of
        transgene insertions at centromeric repeats
      reference_section_type: ABSTRACT
- term:
    id: GO:0140727
    label: siRNA-mediated pericentric heterochromatin formation
  evidence_type: IMP
  original_reference_id: PMID:12193640
  qualifier: involved_in
  review:
    summary: >-
      Swi6 functions in the RNAi-directed pathway that establishes
      pericentromeric heterochromatin and H3K9 methylation through siRNAs from
      centromeric repeats. Core process.
    action: ACCEPT
    reason: Supports siRNA-mediated pericentric heterochromatin formation.
    supported_by:
    - reference_id: PMID:12193640
      supporting_text: >-
        We propose that double-stranded RNA arising from centromeric repeats
        targets formation and maintenance of heterochromatin through RNAi.
      reference_section_type: ABSTRACT
- term:
    id: GO:0033696
    label: heterochromatin boundary formation
  evidence_type: IMP
  original_reference_id: PMID:21211723
  qualifier: involved_in
  review:
    summary: >-
      Swi6 associates with the Asf1/HIRA histone chaperone, which spreads across
      silenced domains to enforce silencing and promote nucleosome occupancy,
      contributing to proper heterochromatin organization at boundaries. Core
      process.
    action: ACCEPT
    reason: Supports role in heterochromatin boundary/nucleosome occupancy.
    supported_by:
    - reference_id: PMID:21211723
      supporting_text: >-
        a histone chaperone complex containing Asf1 and HIRA that spreads across
        silenced domains via its association with Swi6 to enforce
        transcriptional silencing.
      reference_section_type: ABSTRACT
- term:
    id: GO:0140463
    label: chromatin-protein adaptor activity
  evidence_type: EXP
  original_reference_id: PMID:16762840
  qualifier: enables
  review:
    summary: >-
      Swi6/HP1 recruits the JmjC anti-silencing protein Epe1 to heterochromatin,
      balancing opposing chromatin-modifying activities. Core adaptor MF.
    action: ACCEPT
    reason: Direct evidence Swi6 recruits Epe1 (adaptor activity).
    supported_by:
    - reference_id: PMID:16762840
      supporting_text: >-
        Epe1 is recruited to heterochromatic loci by the heterochromatin protein Swi6/HP1.
      reference_section_type: ABSTRACT
- term:
    id: GO:0140463
    label: chromatin-protein adaptor activity
  evidence_type: EXP
  original_reference_id: PMID:17449867
  qualifier: enables
  review:
    summary: >-
      Confirms Swi6 recruits Epe1 to heterochromatin. Core adaptor MF
      (duplicate term, distinct reference).
    action: ACCEPT
    reason: Independent evidence for Swi6-mediated Epe1 recruitment.
    supported_by:
    - reference_id: PMID:17449867
      supporting_text: >-
        We report that Swi6 recruits Epe1 to heterochromatin
      reference_section_type: ABSTRACT
- term:
    id: GO:0003677
    label: DNA binding
  evidence_type: IDA
  original_reference_id: PMID:37400983
  qualifier: enables
  review:
    summary: >-
      PomBase experimental (IDA) annotation. Our cached abstract foregrounds Chp2, the
      other fission-yeast HP1 protein, but the full text (not in our cache) compares both
      HP1 proteins, and PomBase made a direct-assay (IDA) DNA-binding annotation to Swi6
      on its basis. Swi6 is independently well established to bind DNA in a sequence-
      independent manner via its hinge region. DNA binding is thus a genuine biochemical
      property of Swi6 but is ancillary to its core role as an H3K9me reader/effector.
    action: KEEP_AS_NON_CORE
    reason: >-
      Valid PomBase IDA; Swi6 hinge-mediated DNA binding is well established. Retained as
      a real but non-core property rather than a defining function. (An earlier
      assessment that this Chp2-titled paper does not support Swi6 was based on the
      abstract-only cache and overruled the curator without justification.)
    supported_by:
    - reference_id: PMID:37400983
      supporting_text: >-
        Here, we focus on Chp2, one of the two HP1 proteins in fission yeast,
        and investigate how Chp2's DNA-binding ability contributes to its function.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:10801440
  qualifier: enables
  review:
    summary: >-
      This row records the Swi6-Swi6 (chromoshadow-domain) self-interaction; it
      is more informatively captured as identical protein binding /
      homodimerization. Bare "protein binding" is uninformative.
    action: MARK_AS_OVER_ANNOTATED
    reason: Self-interaction better described as homodimerization (GO:0042802).
    supported_by:
    - reference_id: PMID:10801440
      supporting_text: >-
        The 1.9 A crystal structure of the Swi6 CSD is presented here. This
        reveals a novel dimeric structure
      reference_section_type: ABSTRACT
- term:
    id: GO:0003723
    label: RNA binding
  evidence_type: EXP
  original_reference_id: PMID:22683269
  qualifier: enables
  review:
    summary: >-
      Core molecular function. Swi6 binds RNA via its hinge basic patch; RNA
      competes with H3K9me for the chromodomain, and Swi6 sequesters and primes
      heterochromatic transcripts for degradation.
    action: ACCEPT
    reason: Direct in vivo/in vitro evidence for Swi6 RNA binding.
    supported_by:
    - reference_id: PMID:22683269
      supporting_text: >-
        RNA competes with methylated histone H3K9 for binding to the chromodomain of HP1(Swi6).
      reference_section_type: ABSTRACT
- term:
    id: GO:0140463
    label: chromatin-protein adaptor activity
  evidence_type: IPI
  original_reference_id: PMID:18716626
  qualifier: enables
  review:
    summary: >-
      Swi6 recruits meiotic shugoshin Sgo1 to centromeres, the informative MF
      underlying the Swi6-Sgo1 interaction. Core adaptor MF.
    action: ACCEPT
    reason: Direct evidence Swi6 recruits Sgo1 (adaptor activity).
    supported_by:
    - reference_id: PMID:18716626
      supporting_text: >-
        the heterochromatin protein Swi6 associates directly with
        meiosis-specific shugoshin Sgo1, a protector of cohesin at centromeres.
      reference_section_type: ABSTRACT
- term:
    id: GO:1990813
    label: meiotic centromeric cohesion protection in anaphase I
  evidence_type: EXP
  original_reference_id: PMID:18716626
  qualifier: involved_in
  review:
    summary: >-
      By recruiting shugoshin Sgo1, Swi6 protects centromeric cohesin during
      meiosis; forced Sgo1 localization rescues meiotic segregation in swi6
      cells. Core meiotic process.
    action: ACCEPT
    reason: Experimental support for meiotic centromeric cohesion protection.
    supported_by:
    - reference_id: PMID:18716626
      supporting_text: >-
        The forced centromeric localization of Sgo1 restores proper meiotic
        chromosome segregation in swi6 cells.
      reference_section_type: ABSTRACT
- term:
    id: GO:0062072
    label: histone H3K9me2/3 reader activity
  evidence_type: IDA
  original_reference_id: PMID:22683269
  qualifier: enables
  review:
    summary: >-
      Confirms the Swi6 chromodomain reads H3K9me (in competition with RNA).
      Core MF (duplicate term, distinct reference).
    action: ACCEPT
    reason: Direct evidence for H3K9me reader activity.
    supported_by:
    - reference_id: PMID:22683269
      supporting_text: >-
        RNA competes with methylated histone H3K9 for binding to the chromodomain of HP1(Swi6).
      reference_section_type: ABSTRACT
- term:
    id: GO:1990342
    label: heterochromatin island
  evidence_type: IDA
  original_reference_id: PMID:22144463
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 is active at facultative heterochromatin islands that form over
      meiotic genes via RNA elimination machinery. Genuine but specialized
      (facultative) localization; kept as non-core relative to constitutive
      heterochromatin sites.
    action: KEEP_AS_NON_CORE
    reason: Genuine facultative-heterochromatin localization; non-core context.
    supported_by:
    - reference_id: PMID:22144463
      supporting_text: >-
        we describe facultative heterochromatin islands in fission yeast and show
        that their formation at meiotic genes requires factors that eliminate
        meiotic messenger RNAs (mRNAs) during vegetative growth.
      reference_section_type: ABSTRACT
- term:
    id: GO:0006325
    label: chromatin organization
  evidence_type: IMP
  original_reference_id: PMID:19111658
  qualifier: involved_in
  review:
    summary: >-
      Swi6 organizes heterochromatin via a network of associated chromatin
      proteins and contributes to silencing. Correct but high-level; the
      specific heterochromatin formation/silencing terms are preferred.
    action: KEEP_AS_NON_CORE
    reason: Correct but generic relative to specific heterochromatin processes.
    supported_by:
    - reference_id: PMID:19111658
      supporting_text: >-
        Swi6 associates with a different set of nuclear proteins and with
        noncoding centromeric transcripts and is required for efficient
        RNAi-dependent processing of these transcripts.
      reference_section_type: ABSTRACT
- term:
    id: GO:0071962
    label: mitotic sister chromatid cohesion, centromeric
  evidence_type: IMP
  original_reference_id: PMID:31000521
  qualifier: involved_in
  review:
    summary: >-
      Swi6 is required for cohesin (Rad21) enrichment at the pericentromere,
      establishing centromeric sister-chromatid cohesion. Core process.
    action: ACCEPT
    reason: Mutant phenotype supports centromeric cohesion role.
    supported_by:
    - reference_id: PMID:31000521
      supporting_text: >-
        Swi6 is required for cohesin enrichment at the pericentromere.
      reference_section_type: ABSTRACT
- term:
    id: GO:1990758
    label: mitotic sister chromatid biorientation
  evidence_type: IMP
  original_reference_id: PMID:31000521
  qualifier: involved_in
  review:
    summary: >-
      Loss of Swi6 causes defects in establishing bioriented sister
      kinetochores; via cohesin enrichment Swi6 promotes biorientation. Core
      process.
    action: ACCEPT
    reason: Mutant phenotype supports biorientation role.
    supported_by:
    - reference_id: PMID:31000521
      supporting_text: >-
        Loss of Swi6 leads to abnormal mitosis, including defects in the
        establishment of bioriented sister kinetochores and microtubule attachment.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005721
    label: pericentric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:11283354
  qualifier: is_active_in
  review:
    summary: >-
      Direct evidence that Swi6 localizes to pericentric heterochromatin in an
      H3K9me-dependent manner. Core CC.
    action: ACCEPT
    reason: Direct localization evidence.
    supported_by:
    - reference_id: PMID:11283354
      supporting_text: >-
        Localization of Swi6, a homolog of Drosophila HP1, to heterochomatic
        regions is dependent on H3 Lys9 methylation.
      reference_section_type: ABSTRACT
- term:
    id: GO:0031934
    label: mating-type region heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:11283354
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 localizes to mating-type region heterochromatin (H3K9me-dependent).
      Core CC.
    action: ACCEPT
    reason: Direct localization evidence at mat-region heterochromatin.
    supported_by:
    - reference_id: PMID:11283354
      supporting_text: >-
        Localization of Swi6, a homolog of Drosophila HP1, to heterochomatic
        regions is dependent on H3 Lys9 methylation.
      reference_section_type: ABSTRACT
- term:
    id: GO:0003723
    label: RNA binding
  evidence_type: IDA
  original_reference_id: PMID:19111658
  qualifier: enables
  review:
    summary: >-
      Swi6 associates with noncoding centromeric transcripts (Clr4-dependent),
      consistent with RNA binding. Core MF (duplicate term, distinct reference).
    action: ACCEPT
    reason: Direct evidence Swi6 associates with heterochromatic RNAs.
    supported_by:
    - reference_id: PMID:19111658
      supporting_text: >-
        Swi6 associates with a different set of nuclear proteins and with
        noncoding centromeric transcripts
      reference_section_type: ABSTRACT
- term:
    id: GO:0005721
    label: pericentric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:19965387
  qualifier: is_active_in
  review:
    summary: >-
      Direct localization of Swi6 to pericentric heterochromatin (shugoshin
      localization study). Core CC.
    action: ACCEPT
    reason: Direct localization evidence.
    supported_by:
    - reference_id: PMID:19965387
      supporting_text: >-
        Bub1 phosphorylates the conserved serine 121 of histone H2A in fission
        yeast Schizosaccharomyces pombe.
      reference_section_type: ABSTRACT
- term:
    id: GO:0031934
    label: mating-type region heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:19965387
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 localizes to mating-type region heterochromatin. Core CC (duplicate
      term, distinct reference).
    action: ACCEPT
    reason: Direct localization evidence at mat-region heterochromatin.
    supported_by:
    - reference_id: PMID:11780129
      supporting_text: >-
        Cohesin is also enriched at the mating-type heterochromatic region in a manner that
        depends on Swi6 and is required to preserve the genomic integrity of this locus.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:29136238
  qualifier: enables
  review:
    summary: >-
      Bare "protein binding"; this study concerns H3Y41 phosphorylation
      regulating Swi6/Chp1 localization at centromeric heterochromatin rather
      than a discrete informative binding partner. Uninformative MF.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF.
    supported_by:
    - reference_id: PMID:29136238
      supporting_text: >-
        it promotes the binding of Chp1 to histone H3 and the exclusion of Swi6.
      reference_section_type: ABSTRACT
- term:
    id: GO:0000792
    label: heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:26438724
  qualifier: is_active_in
  review:
    summary: >-
      Direct evidence Swi6 is a dynamic component of heterochromatin. Core CC
      (generic heterochromatin term).
    action: ACCEPT
    reason: Direct localization in heterochromatin.
    supported_by:
    - reference_id: PMID:26438724
      supporting_text: >-
        the fission yeast HP1 protein Swi6 exists as a single highly dynamic
        population that rapidly exchanges in cis and in trans between different
        heterochromatic regions.
      reference_section_type: ABSTRACT
- term:
    id: GO:0033696
    label: heterochromatin boundary formation
  evidence_type: IMP
  original_reference_id: PMID:26438724
  qualifier: involved_in
  review:
    summary: >-
      Swi6 dimerization demarcates constitutive heterochromatin from
      neighboring euchromatin and confines its spread, a genuine boundary
      function. Core process.
    action: ACCEPT
    reason: Strong evidence for a heterochromatin demarcation/confinement role.
    supported_by:
    - reference_id: PMID:26438724
      supporting_text: >-
        a surprising role for Swi6 dimerization in demarcating constitutive
        heterochromatin from neighboring euchromatin.
      reference_section_type: ABSTRACT
- term:
    id: GO:0044820
    label: mitotic telomere tethering at nuclear periphery
  evidence_type: IMP
  original_reference_id: PMID:25778919
  qualifier: involved_in
  review:
    summary: >-
      Swi6/HP1 (with cohesin Rad21) is associated with telomere clustering;
      Aurora B-driven telomere dispersion involves dissociation of Swi6 from
      telomeres. Genuine but specialized telomere-organization role; non-core
      relative to heterochromatin silencing.
    action: KEEP_AS_NON_CORE
    reason: Genuine telomere-organization role but a peripheral context.
    supported_by:
    - reference_id: PMID:25778919
      supporting_text: >-
        Dispersion is promoted by the dissociation of Swi6/HP1 and cohesin Rad21
        from telomeres
      reference_section_type: ABSTRACT
- term:
    id: GO:0006325
    label: chromatin organization
  evidence_type: IMP
  original_reference_id: PMID:9710635
  qualifier: involved_in
  review:
    summary: >-
      Swi6 contributes to chromatin remodeling/organization underlying
      mating-type silencing. Correct but high-level; specific heterochromatin
      terms are preferred.
    action: KEEP_AS_NON_CORE
    reason: Correct but generic.
    supported_by:
    - reference_id: PMID:9710635
      supporting_text: >-
        a similar silencing mechanism may operate in the distantly related yeast
        Schizosaccharomyces pombe.
      reference_section_type: ABSTRACT
- term:
    id: GO:0000785
    label: chromatin
  evidence_type: IDA
  original_reference_id: PMID:21151114
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 is chromatin-associated; correct but generic relative to the
      heterochromatin subdomain terms.
    action: KEEP_AS_NON_CORE
    reason: Correct but generic CC.
    supported_by:
    - reference_id: PMID:21151114
      supporting_text: >-
        the RNAi proteins Dcr1 and Rdp1 physically associate with some
        euchromatic genes, noncoding RNA genes and retrotransposon long terminal repeats
      reference_section_type: ABSTRACT
- term:
    id: GO:0000792
    label: heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:11069763
  qualifier: is_active_in
  review:
    summary: >-
      GFP-Swi6 is concentrated at heterochromatic centromeres and telomeres.
      Core CC (generic heterochromatin term).
    action: ACCEPT
    reason: Direct localization in heterochromatin.
    supported_by:
    - reference_id: PMID:11069763
      supporting_text: >-
        GFP-Swi6p localises to the nucleus and is concentrated at the
        heterochromatic centromeres and telomeres.
      reference_section_type: ABSTRACT
- term:
    id: GO:0000779
    label: condensed chromosome, centromeric region
  evidence_type: IDA
  original_reference_id: PMID:7660126
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 localizes to centromeres and is required for their proper function
      during mitosis. Core CC.
    action: ACCEPT
    reason: Direct localization at centromeres.
    supported_by:
    - reference_id: PMID:7660126
      supporting_text: >-
        Thus, Swi6p is located at fission yeast centromeres and is required for
        their proper function.
      reference_section_type: ABSTRACT
- term:
    id: GO:0031934
    label: mating-type region heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:7660126
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 localizes to the silent mating-type loci heterochromatin. Core CC.
    action: ACCEPT
    reason: Direct localization at mat-region heterochromatin.
    supported_by:
    - reference_id: PMID:7660126
      supporting_text: >-
        Swi6p localizes with these three chromosomal regions.
      reference_section_type: ABSTRACT
- term:
    id: GO:0140720
    label: subtelomeric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:7660126
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 localizes to telomeric/subtelomeric heterochromatin. Core CC.
    action: ACCEPT
    reason: Direct localization at subtelomeric heterochromatin.
    supported_by:
    - reference_id: PMID:7660126
      supporting_text: >-
        the silent mating-type loci, centromeres, and telomeres are assembled
        into silent heterochromatin-like domains.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005721
    label: pericentric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:10766735
  qualifier: is_active_in
  review:
    summary: >-
      Direct ChIP mapping shows Swi6 confined to (and spreading across)
      pericentromeric outer repeats. Core CC.
    action: ACCEPT
    reason: Direct localization at pericentric repeats.
    supported_by:
    - reference_id: PMID:10766735
      supporting_text: >-
        Swi6 and Chp1 are confined to the flanking outer repeats and Swi6 can
        spread across at least 3 kb of extraneous chromatin in cen1.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005721
    label: pericentric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:11553715
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 binds the pericentromeric repeats flanking the central core,
      consistent with conserved centromere domain organization. Core CC.
    action: ACCEPT
    reason: Direct localization at pericentromeric repeats.
    supported_by:
    - reference_id: PMID:11553715
      supporting_text: >-
        the Swi6 protein binds the surrounding repeats.
      reference_section_type: ABSTRACT
- term:
    id: GO:0005721
    label: pericentric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:20299449
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 occupies pericentric heterochromatin during the inactive state,
      regulated by an H3K4ac-mediated chromodomain switch. Core CC.
    action: ACCEPT
    reason: Direct localization at pericentric heterochromatin.
    supported_by:
    - reference_id: PMID:20299449
      supporting_text: >-
        Chp2/Swi6 (HP1 homologs) are recruited during the inactive state.
      reference_section_type: ABSTRACT
- term:
    id: GO:0007533
    label: mating type switching
  evidence_type: IMP
  original_reference_id: PMID:1620099
  qualifier: involved_in
  review:
    summary: >-
      swi6 mutation reduces mating-type switching and disrupts the chromatin
      structure of the mating-type region. Core process.
    action: ACCEPT
    reason: Classic mutant evidence for swi6 in mating-type switching.
    supported_by:
    - reference_id: PMID:1620099
      supporting_text: >-
        Besides reducing MT switching, the swi6 mutation leads to deletions in
        the MT region caused by intrachromosomal cross-overs between two paired
        cassettes.
      reference_section_type: ABSTRACT
- term:
    id: GO:0030466
    label: silent mating-type cassette heterochromatin formation
  evidence_type: IMP
  original_reference_id: PMID:1620099
  qualifier: involved_in
  review:
    summary: >-
      swi6 is required for repression/heterochromatin of the silent mating-type
      cassettes; loss permits expression of both cassettes and recombination in
      the normally inert K region. Core process.
    action: ACCEPT
    reason: Mutant evidence for silent mat-cassette heterochromatin.
    supported_by:
    - reference_id: PMID:1620099
      supporting_text: >-
        swi6 also allows the simultaneous expression of two different cassettes
        in the same haploid cell.
      reference_section_type: ABSTRACT
- term:
    id: GO:0030466
    label: silent mating-type cassette heterochromatin formation
  evidence_type: IMP
  original_reference_id: PMID:8138176
  qualifier: involved_in
  review:
    summary: >-
      swi6 (with clr1) derepresses the silent mating-type loci and allows K-
      region recombination when mutated, supporting its role in silent cassette
      heterochromatin. Core process (duplicate term, distinct reference).
    action: ACCEPT
    reason: Mutant evidence for silent mat-cassette heterochromatin.
    supported_by:
    - reference_id: PMID:8138176
      supporting_text: >-
        mutations in two genes, clr1 and swi6, had been shown to allow both
        expression of the silent loci and recombination in the K region.
      reference_section_type: ABSTRACT
- term:
    id: GO:0062072
    label: histone H3K9me2/3 reader activity
  evidence_type: IDA
  original_reference_id: PMID:22727667
  qualifier: enables
  review:
    summary: >-
      This reference characterizes the Chp1 chromodomain's nucleic-acid binding
      enhanced by H3K9me; it concerns the chromodomain protein family context.
      Swi6 H3K9me reader activity is firmly established by other references
      (PMID:11242054, PMID:22683269), so the term is correct for Swi6 even
      though this particular citation centers on Chp1.
    action: ACCEPT
    reason: H3K9me reader activity is well established for Swi6 (core MF).
    supported_by:
    - reference_id: PMID:11242054
      supporting_text: >-
        The chromo domain of HP1 is identified as its methyl-lysine-binding domain.
      reference_section_type: ABSTRACT
- term:
    id: GO:0007534
    label: gene conversion at mating-type locus
  evidence_type: IMP
  original_reference_id: PMID:6587363
  qualifier: involved_in
  review:
    summary: >-
      swi6 belongs to the group of switching genes affecting the efficient
      utilization of the mat1 cut and the directionality of switching (gene
      conversion). Core process.
    action: ACCEPT
    reason: Classic genetic evidence placing swi6 in mat switching/conversion.
    supported_by:
    - reference_id: PMID:6587363
      supporting_text: >-
        The remaining three ( swi2 , -5, -6) have normal levels of cut, do not
        make errors of resolution, and possibly are required either for
        efficient utilization of the cut or determining the directionality of switching.
      reference_section_type: ABSTRACT
- term:
    id: GO:0003723
    label: RNA binding
  evidence_type: IDA
  original_reference_id: PMID:22683269
  qualifier: enables
  review:
    summary: >-
      Swi6 RNA binding via the hinge (duplicate of the RNA-binding annotation
      from the same reference). Core MF.
    action: ACCEPT
    reason: Direct evidence for Swi6 RNA binding.
    supported_by:
    - reference_id: PMID:22683269
      supporting_text: >-
        Stimulated by positively charged residues in the hinge region, RNA
        competes with methylated histone H3K9 for binding to the chromodomain of HP1(Swi6).
      reference_section_type: ABSTRACT
- term:
    id: GO:0005721
    label: pericentric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:20929775
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 localizes to pericentric heterochromatin (inner-centromere/
      shugoshin study). Core CC.
    action: ACCEPT
    reason: Direct localization at pericentric heterochromatin.
    supported_by:
    - reference_id: PMID:20929775
      supporting_text: >-
        phosphorylated H2A-S121 facilitates the binding of shugoshin, the
        centromeric CPC adaptor.
      reference_section_type: ABSTRACT
- term:
    id: GO:0031934
    label: mating-type region heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:20929775
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 localizes to mating-type region heterochromatin. Core CC (duplicate
      term, distinct reference).
    action: ACCEPT
    reason: Direct localization at mat-region heterochromatin.
    supported_by:
    - reference_id: PMID:20929775
      supporting_text: >-
        the inner centromere is defined by intersection of two histone kinases.
      reference_section_type: ABSTRACT
- term:
    id: GO:0140720
    label: subtelomeric heterochromatin
  evidence_type: IDA
  original_reference_id: PMID:20929775
  qualifier: is_active_in
  review:
    summary: >-
      Swi6 localizes to subtelomeric heterochromatin. Core CC (duplicate term,
      distinct reference).
    action: ACCEPT
    reason: Direct localization at subtelomeric heterochromatin.
    supported_by:
    - reference_id: PMID:20929775
      supporting_text: >-
        For proper partitioning of chromosomes in mitosis, the chromosomal
        passenger complex (CPC) including Aurora B and survivin must be localized
        at the center of paired kinetochores
      reference_section_type: ABSTRACT
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:20929775
  qualifier: enables
  review:
    summary: >-
      Bare "protein binding" (interaction with Hrk1/Haspin context). The
      informative MF is Swi6's chromatin-protein adaptor activity; the generic
      term is uninformative.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF.
    supported_by:
    - reference_id: PMID:20929775
      supporting_text: >-
        Haspin colocalizes with cohesin by associating with Pds5, whereas Bub1
        localizes at kinetochores.
      reference_section_type: ABSTRACT
core_functions:
- description: >-
    Reads the H3K9me2/me3 heterochromatin mark via its chromodomain, providing
    the recognition step that targets Swi6 to Clr4-methylated nucleosomes.
  supported_by:
  - reference_id: PMID:11242054
    supporting_text: >-
      HP1 can bind with high affinity to histone H3 methylated at lysine 9 but
      not at lysine 4. The chromo domain of HP1 is identified as its
      methyl-lysine-binding domain.
    reference_section_type: ABSTRACT
- description: >-
    Homodimerizes/oligomerizes via its chromoshadow domain to form a
    spreading-competent, chromatin-compacting platform and protein-interaction
    pit.
  supported_by:
  - reference_id: PMID:10801440
    supporting_text: >-
      Dimerisation through the CSD of HP1-like proteins results in the
      simultaneous formation of a putative protein-protein interaction pit
    reference_section_type: ABSTRACT
  - reference_id: PMID:23485968
    supporting_text: >-
      binding of the key S. pombe HP1 protein, Swi6, to methylated nucleosomes
      drives a switch from an auto-inhibited state to a spreading-competent state.
    reference_section_type: ABSTRACT
- description: >-
    Acts as a chromatin-protein adaptor/scaffold, recruiting effectors to
    heterochromatin including cohesin (Psc3), the JmjC protein Epe1, the RNAi
    bridge Ers1/RDRC, the switching factor Swi2, and shugoshin Sgo1.
  supported_by:
  - reference_id: PMID:11780129
    supporting_text: >-
      a cohesin subunit Psc3 interacts with Swi6 and its mouse homologue HP1.
    reference_section_type: ABSTRACT
  - reference_id: PMID:16762840
    supporting_text: >-
      Epe1 is recruited to heterochromatic loci by the heterochromatin protein Swi6/HP1.
    reference_section_type: ABSTRACT
- description: >-
    Mediates transcriptional and co-transcriptional gene silencing and assembly,
    demarcation and confinement of heterochromatin at centromeres, telomeres,
    the silent mating-type cassettes and rDNA.
  supported_by:
  - reference_id: PMID:26438724
    supporting_text: >-
      a surprising role for Swi6 dimerization in demarcating constitutive
      heterochromatin from neighboring euchromatin.
    reference_section_type: ABSTRACT
- description: >-
    Enriches cohesin at the pericentromere to ensure centromeric sister-
    chromatid cohesion, biorientation and accurate chromosome segregation.
  supported_by:
  - reference_id: PMID:31000521
    supporting_text: >-
      Swi6 is required for cohesin enrichment at the pericentromere.
    reference_section_type: ABSTRACT
- description: >-
    Required for mating-type switching, including correct donor selection
    (directionality), by maintaining silent-cassette heterochromatin and
    recruiting the switching factor Swi2.
  supported_by:
  - reference_id: PMID:1620099
    supporting_text: >-
      Besides reducing MT switching, the swi6 mutation leads to deletions in the
      MT region caused by intrachromosomal cross-overs between two paired cassettes.
    reference_section_type: ABSTRACT
  - reference_id: PMID:36951094
    supporting_text: >-
      the Swi6-binding site was required for Swi2 localization at SRE2 to select
      mat2-P in M cells.
    reference_section_type: ABSTRACT
- description: >-
    Binds RNA via its basic hinge, sequestering and priming heterochromatic
    transcripts for degradation in competition with H3K9me chromodomain binding.
  supported_by:
  - reference_id: PMID:22683269
    supporting_text: >-
      the fission yeast HP1(Swi6) protein guarantees tight repression of
      heterochromatic genes through RNA sequestration and degradation.
    reference_section_type: ABSTRACT
proposed_new_terms: []
suggested_questions:
- question: >-
    What determines the partitioning of effector recruitment between the two
    fission yeast HP1 proteins (Swi6 vs Chp2), and how is Swi6's bifunctional
    chromatin- and RNA-binding balanced in vivo?
- question: >-
    How does Swi6 oligomerization/phase behavior on H3K9me chromatin quantitatively
    contribute to silencing versus boundary confinement at different loci?
suggested_experiments:
- description: >-
      Separation-of-function mutants (chromodomain reader-dead vs CSD dimer-dead vs
      hinge RNA/DNA-binding-dead) assayed in parallel for silencing, cohesin
      enrichment, donor selection, and boundary confinement to dissect which core
      function drives each phenotype.
- description: >-
      Quantitative ChIP-seq/CUT&RUN of Swi6 and its recruited effectors (Psc3,
      Clr3/SHREC, Epe1, Ers1) in wild-type and Swi6 phospho-site mutants to map
      how post-translational modification reprograms the adaptor interactome.
references:
- id: file:interpro/panther/PTHR22812/PTHR22812-review.md
  title: 'PANTHER family review PTHR22812: IBA propagation assessment for swi6'
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000044
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location
    vocabulary mapping, accompanied by conservative changes to GO terms applied by
    UniProt
  findings: []
- id: GO_REF:0000117
  title: Electronic Gene Ontology annotations created by ARBA machine learning models
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:10766735
  title: Distinct protein interaction domains and protein spreading in a complex centromere.
  findings:
  - statement: >-
      Swi6 is confined to the pericentromeric flanking outer repeats and can spread
      across at least 3 kb of chromatin in cen1.
    supporting_text: >-
      Swi6 and Chp1 are confined to the flanking outer repeats and Swi6 can spread
      across at least 3 kb of extraneous chromatin in cen1.
    reference_section_type: ABSTRACT
- id: PMID:10801440
  title: Dimerisation of a chromo shadow domain and distinctions from the chromodomain
    as revealed by structural analysis.
  findings:
  - statement: >-
      The Swi6 chromoshadow domain forms a dimer creating a protein-interaction pit
      for targeting effectors to chromatin.
    supporting_text: >-
      Dimerisation through the CSD of HP1-like proteins results in the simultaneous
      formation of a putative protein-protein interaction pit
    reference_section_type: ABSTRACT
- id: PMID:11069763
  title: Live analysis of lagging chromosomes during anaphase and their effect on
    spindle elongation rate in fission yeast.
  findings:
  - statement: GFP-Swi6 localizes to the nucleus and concentrates at centromeres and telomeres.
    supporting_text: >-
      GFP-Swi6p localises to the nucleus and is concentrated at the heterochromatic
      centromeres and telomeres.
    reference_section_type: ABSTRACT
- id: PMID:11242054
  title: Selective recognition of methylated lysine 9 on histone H3 by the HP1 chromo
    domain.
  findings:
  - statement: The HP1/Swi6 chromodomain is the methyl-lysine-binding domain selective for H3K9me.
    supporting_text: >-
      HP1 can bind with high affinity to histone H3 methylated at lysine 9 but not
      at lysine 4. The chromo domain of HP1 is identified as its methyl-lysine-binding domain.
    reference_section_type: ABSTRACT
- id: PMID:11283354
  title: Role of histone H3 lysine 9 methylation in epigenetic control of heterochromatin
    assembly.
  findings:
  - statement: Swi6 localization to heterochromatin depends on Clr4-mediated H3K9 methylation.
    supporting_text: >-
      Localization of Swi6, a homolog of Drosophila HP1, to heterochomatic regions
      is dependent on H3 Lys9 methylation.
    reference_section_type: ABSTRACT
- id: PMID:11553715
  title: The domain structure of centromeres is conserved from fission yeast to humans.
  findings:
  - statement: Swi6 binds the pericentromeric repeats flanking the central core.
    supporting_text: 'the Swi6 protein binds the surrounding repeats.'
    reference_section_type: ABSTRACT
- id: PMID:11780129
  title: Recruitment of cohesin to heterochromatic regions by Swi6/HP1 in fission
    yeast.
  findings:
  - statement: Swi6 recruits cohesin to centromeric and mating-type heterochromatin via Psc3.
    supporting_text: >-
      a cohesin subunit Psc3 interacts with Swi6 and its mouse homologue HP1.
    reference_section_type: ABSTRACT
- id: PMID:12193640
  title: Regulation of heterochromatic silencing and histone H3 lysine-9 methylation
    by RNAi.
  findings:
  - statement: RNAi from centromeric repeats targets heterochromatin formation in which Swi6 acts.
    supporting_text: >-
      We propose that double-stranded RNA arising from centromeric repeats targets
      formation and maintenance of heterochromatin through RNAi.
    reference_section_type: ABSTRACT
- id: PMID:14625560
  title: Hsk1-Dfp1 is required for heterochromatin-mediated cohesion at centromeres.
  findings: []
- id: PMID:14663140
  title: Two different Swi5-containing protein complexes are involved in mating-type
    switching and recombination repair in fission yeast.
  findings: []
- id: PMID:15292231
  title: Regulation of Swi6/HP1-dependent heterochromatin assembly by cooperation
    of components of the mitogen-activated protein kinase pathway and a histone deacetylase
    Clr6.
  findings:
  - statement: A Swi6-dependent pathway assembles heterochromatin across the silent mating-type region.
    supporting_text: >-
      a stochastic Swi6 (the fission yeast HP1 homolog)-dependent mechanism that is
      not fully understood.
    reference_section_type: ABSTRACT
- id: PMID:15372076
  title: A chromodomain protein, Chp1, is required for the establishment of heterochromatin
    in fission yeast.
  findings:
  - statement: Swi6 (with Chp2) maintains residual H3K9 methylation at centromeres, mat region and telomeres.
    supporting_text: 'Swi6 and Chp2 are critical to maintaining this residual methylation.'
    reference_section_type: ABSTRACT
- id: PMID:16246721
  title: The nucleation and maintenance of heterochromatin by a histone deacetylase
    in fission yeast.
  findings:
  - statement: Clr3 spreading across the silent mat domain requires heterochromatin proteins including Swi6/HP1.
    supporting_text: >-
      Clr3 spreads across the 20 kb silenced domain that requires its own HDAC
      activity and heterochromatin proteins including Swi6/HP1.
    reference_section_type: ABSTRACT
- id: PMID:16762840
  title: Swi6/HP1 recruits a JmjC domain protein to facilitate transcription of heterochromatic
    repeats.
  findings:
  - statement: Swi6/HP1 recruits the anti-silencing JmjC protein Epe1 to heterochromatin.
    supporting_text: >-
      Epe1 is recruited to heterochromatic loci by the heterochromatin protein Swi6/HP1.
    reference_section_type: ABSTRACT
- id: PMID:17449867
  title: Interaction of Epe1 with the heterochromatin assembly pathway in Schizosaccharomyces
    pombe.
  findings:
  - statement: Swi6 recruits Epe1 to heterochromatin.
    supporting_text: 'We report that Swi6 recruits Epe1 to heterochromatin'
    reference_section_type: ABSTRACT
- id: PMID:17512405
  title: RNAi-dependent and -independent RNA turnover mechanisms contribute to heterochromatic
    gene silencing.
  findings:
  - statement: RNAi is required for heterochromatin-dependent silencing at centromeric repeats.
    supporting_text: >-
      the RNAi pathway is required for heterochromatin-dependent silencing of
      transgene insertions at centromeric repeats
    reference_section_type: ABSTRACT
- id: PMID:18716626
  title: Heterochromatin links to centromeric protection by recruiting shugoshin.
  findings:
  - statement: Swi6 directly recruits shugoshin Sgo1 to protect centromeric cohesin in meiosis.
    supporting_text: >-
      the heterochromatin protein Swi6 associates directly with meiosis-specific
      shugoshin Sgo1, a protector of cohesin at centromeres.
    reference_section_type: ABSTRACT
- id: PMID:18761674
  title: Fission yeast chromatin assembly factor 1 assists in the replication-coupled
    maintenance of heterochromatin.
  findings: []
- id: PMID:18809570
  title: Balance between distinct HP1 family proteins controls heterochromatin assembly
    in fission yeast.
  findings:
  - statement: Swi6 and Chp2 play distinct, dose-dependent roles in assembling repressive heterochromatin.
    supporting_text: >-
      both Swi6 and Chp2 are required for the assembly of fully repressive heterochromatin
    reference_section_type: ABSTRACT
- id: PMID:19111658
  title: HP1 proteins form distinct complexes and mediate heterochromatic gene silencing
    by nonoverlapping mechanisms.
  findings:
  - statement: Swi6 associates with noncoding centromeric transcripts and is required for RNAi processing into siRNAs.
    supporting_text: >-
      Swi6 associates with a different set of nuclear proteins and with noncoding
      centromeric transcripts and is required for efficient RNAi-dependent processing
      of these transcripts.
    reference_section_type: ABSTRACT
- id: PMID:19136623
  title: Phosphorylation of Swi6/HP1 regulates transcriptional gene silencing at heterochromatin.
  findings:
  - statement: Swi6 recruits SHREC, Epe1 and cohesin; CK2 phosphorylation of Swi6 controls TGS.
    supporting_text: >-
      a HP1 homolog Swi6 recruits SHREC, Epe1, and cohesin, which are involved in
      transcriptional gene silencing (TGS), transcriptional activation, and sister
      chromatid cohesion, respectively.
    reference_section_type: ABSTRACT
- id: PMID:19443688
  title: Diverse roles of HP1 proteins in heterochromatin assembly and functions in
    fission yeast.
  findings:
  - statement: Swi6 and Chp2 with HDAC complexes limit Pol II occupancy across pericentromeric heterochromatin.
    supporting_text: >-
      Swi6 and Chp2 proteins and their associated HDAC complexes have overlapping
      functions in limiting Pol II occupancy across pericentromeric heterochromatin domains.
    reference_section_type: ABSTRACT
- id: PMID:19965387
  title: Phosphorylation of H2A by Bub1 prevents chromosomal instability through localizing
    shugoshin.
  findings: []
- id: PMID:20299449
  title: A chromodomain switch mediated by histone H3 Lys 4 acetylation regulates
    heterochromatin assembly.
  findings:
  - statement: Chp2/Swi6 are recruited to pericentric heterochromatin during the inactive state.
    supporting_text: 'Chp2/Swi6 (HP1 homologs) are recruited during the inactive state.'
    reference_section_type: ABSTRACT
- id: PMID:20929775
  title: Two histone marks establish the inner centromere and chromosome bi-orientation.
  findings: []
- id: PMID:21151114
  title: Dicer associates with chromatin to repress genome activity in Schizosaccharomyces
    pombe.
  findings: []
- id: PMID:21211723
  title: Asf1/HIRA facilitate global histone deacetylation and associate with HP1
    to promote nucleosome occupancy at heterochromatic loci.
  findings:
  - statement: An Asf1/HIRA histone chaperone spreads across silenced domains via association with Swi6.
    supporting_text: >-
      a histone chaperone complex containing Asf1 and HIRA that spreads across
      silenced domains via its association with Swi6 to enforce transcriptional silencing.
    reference_section_type: ABSTRACT
- id: PMID:22144463
  title: RNA elimination machinery targeting meiotic mRNAs promotes facultative heterochromatin
    formation.
  findings:
  - statement: Facultative heterochromatin islands form at meiotic genes via RNA elimination machinery.
    supporting_text: >-
      we describe facultative heterochromatin islands in fission yeast and show that
      their formation at meiotic genes requires factors that eliminate meiotic
      messenger RNAs (mRNAs) during vegetative growth.
    reference_section_type: ABSTRACT
- id: PMID:22474355
  title: Heterochromatin protein 1 homologue Swi6 acts in concert with Ers1 to regulate
    RNAi-directed heterochromatin assembly.
  findings:
  - statement: Swi6 recruits RDRC to heterochromatin through the RNAi intermediate Ers1.
    supporting_text: >-
      we demonstrate that Swi6 recruits RDRC to heterochromatin through Ers1, an
      RNAi factor intermediate.
    reference_section_type: ABSTRACT
- id: PMID:22683269
  title: HP1(Swi6) mediates the recognition and destruction of heterochromatic RNA
    transcripts.
  findings:
  - statement: Swi6 binds RNA via its hinge; RNA competes with H3K9me for the chromodomain.
    supporting_text: >-
      Stimulated by positively charged residues in the hinge region, RNA competes
      with methylated histone H3K9 for binding to the chromodomain of HP1(Swi6).
    reference_section_type: ABSTRACT
- id: PMID:22727667
  title: Intrinsic nucleic acid-binding activity of Chp1 chromodomain is required
    for heterochromatic gene silencing.
  findings: []
- id: PMID:22990236
  title: Hrp3 controls nucleosome positioning to suppress non-coding transcription
    in eu- and heterochromatin.
  findings: []
- id: PMID:23485968
  title: A conformational switch in HP1 releases auto-inhibition to drive heterochromatin
    assembly.
  findings:
  - statement: Swi6 binding to methylated nucleosomes switches it from auto-inhibited to spreading-competent oligomers.
    supporting_text: >-
      binding of the key S. pombe HP1 protein, Swi6, to methylated nucleosomes
      drives a switch from an auto-inhibited state to a spreading-competent state.
    reference_section_type: ABSTRACT
- id: PMID:25245948
  title: Tls1 regulates splicing of shelterin components to control telomeric heterochromatin
    assembly and telomere length.
  findings:
  - statement: Telomeric heterochromatin assembly requires multiple factors including Tls1.
    supporting_text: >-
      we comprehensively identified factors required for telomeric heterochromatin
      assembly, including a novel gene tls1+.
    reference_section_type: ABSTRACT
- id: PMID:25778919
  title: Aurora B prevents chromosome arm separation defects by promoting telomere
    dispersion and disjunction.
  findings:
  - statement: Telomere dispersion is promoted by dissociation of Swi6/HP1 and cohesin Rad21 from telomeres.
    supporting_text: >-
      Dispersion is promoted by the dissociation of Swi6/HP1 and cohesin Rad21 from telomeres
    reference_section_type: ABSTRACT
- id: PMID:26438724
  title: H3K9 methylation extends across natural boundaries of heterochromatin in
    the absence of an HP1 protein.
  findings:
  - statement: Swi6 dimerization demarcates and confines constitutive heterochromatin rather than promoting its spread.
    supporting_text: >-
      a surprising role for Swi6 dimerization in demarcating constitutive
      heterochromatin from neighboring euchromatin.
    reference_section_type: ABSTRACT
- id: PMID:29136238
  title: Regulation of transcriptional silencing and chromodomain protein localization
    at centromeric heterochromatin by histone H3 tyrosine 41 phosphorylation in fission
    yeast.
  findings: []
- id: PMID:29852001
  title: New insights into donor directionality of mating-type switching in Schizosaccharomyces
    pombe.
  findings:
  - statement: Mating-type switching donor selection is regulated by heterochromatin and the HP1-like protein Swi6.
    supporting_text: >-
      Mating-type switching in Schizosaccharomyces pombe entails programmed gene
      conversion events regulated by DNA replication, heterochromatin, and the
      HP1-like chromodomain protein Swi6.
    reference_section_type: ABSTRACT
- id: PMID:31000521
  title: Overlapping Roles in Chromosome Segregation for Heterochromatin Protein 1
    (Swi6) and DDK in Schizosaccharomyces pombe.
  findings:
  - statement: Swi6 is required for cohesin enrichment at the pericentromere and for sister-kinetochore biorientation.
    supporting_text: >-
      Swi6 is required for cohesin enrichment at the pericentromere.
    reference_section_type: ABSTRACT
- id: PMID:36951094
  title: Fission yeast Swi2 designates cell-type specific donor and stimulates Rad51-driven
    strand exchange for mating-type switching.
  findings:
  - statement: A Swi6-binding site in Swi2 is required for Swi2 localization at SRE2 to select the mat2-P donor.
    supporting_text: >-
      the Swi6-binding site was required for Swi2 localization at SRE2 to select
      mat2-P in M cells.
    reference_section_type: ABSTRACT
- id: PMID:37400983
  title: Cooperative DNA-binding activities of Chp2 are critical for its function
    in heterochromatin assembly.
  findings:
  - statement: >-
      This study characterizes cooperative DNA-binding by HP1 proteins in fission yeast.
      The cached abstract foregrounds Chp2, but PomBase used the full text to make a
      direct-assay (IDA) DNA-binding annotation to Swi6 (the other HP1 protein), retained
      here as a non-core, hinge-mediated property of Swi6.
    supporting_text: >-
      Here, we focus on Chp2, one of the two HP1 proteins in fission yeast, and
      investigate how Chp2's DNA-binding ability contributes to its function.
    reference_section_type: ABSTRACT
- id: PMID:39747188
  title: PhpC(NF-Y) transcription factor infiltrates heterochromatin to generate cryptic
    intron-containing transcripts crucial for small RNA production.
  findings:
  - statement: TF-driven transcription of heterochromatic repeats produces siRNAs critical for heterochromatin nucleation.
    supporting_text: >-
      siRNA production by this TF-mediated transcription pathway is critical for
      heterochromatin nucleation at target repeat loci.
    reference_section_type: ABSTRACT
- id: PMID:6587363
  title: Genes required for initiation and resolution steps of mating-type switching
    in fission yeast.
  findings:
  - statement: swi6 is required for efficient utilization of the mat1 cut and switching directionality.
    supporting_text: >-
      The remaining three ( swi2 , -5, -6) have normal levels of cut, do not make
      errors of resolution, and possibly are required either for efficient
      utilization of the cut or determining the directionality of switching.
    reference_section_type: ABSTRACT
- id: PMID:7660126
  title: 'The chromodomain protein Swi6: a key component at fission yeast centromeres.'
  findings:
  - statement: Swi6 localizes to centromeres, mating-type loci and telomeres and is required for centromere function.
    supporting_text: >-
      Thus, Swi6p is located at fission yeast centromeres and is required for their proper function.
    reference_section_type: ABSTRACT
- id: PMID:8138176
  title: Mutations in rik1, clr2, clr3 and clr4 genes asymmetrically derepress the
    silent mating-type loci in fission yeast.
  findings:
  - statement: swi6 (with clr1) allows expression of the silent mating-type loci and K-region recombination when mutated.
    supporting_text: >-
      mutations in two genes, clr1 and swi6, had been shown to allow both expression
      of the silent loci and recombination in the K region.
    reference_section_type: ABSTRACT
- id: PMID:9710635
  title: A novel function of the DNA repair gene rhp6 in mating-type silencing by
    chromatin remodeling in fission yeast.
  findings: []
- id: PMID:1620099
  title: The switching gene swi6 affects recombination and gene expression in the
    mating-type region of Schizosaccharomyces pombe.
  findings:
  - statement: swi6 mutation reduces mating-type switching and derepresses the silent cassettes, allowing K-region recombination.
    supporting_text: >-
      swi6 also allows the simultaneous expression of two different cassettes in the same haploid cell.
    reference_section_type: ABSTRACT