dimA

id: Q54XG7
gene_symbol: dimA
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:44689
  label: Dictyostelium discoideum
description: DimA (Basic-leucine zipper transcription factor A; DIF insensitive
  mutant A) is a bZIP/bRLZ transcription factor of the social amoeba Dictyostelium
  discoideum that is required for cellular responses to the chlorinated signalling
  molecule DIF-1. Acting in the nucleus, DimA binds DNA as a dimer through its basic
  region-leucine zipper and both activates prestalk (pstO) gene expression and
  represses prespore gene expression downstream of DIF-1. It forms homodimers and
  heterodimerizes with the related bZIP factor DimB, and in response to DIF-1 it
  accumulates rapidly in the nucleus, a relocalization that depends on DimB. Through
  this transcriptional control DimA integrates DIF-1 signalling with cell-type
  differentiation and patterning during multicellular development, being required
  for stalk-cell differentiation and for repression of the spore fate; loss of dimA
  produces long thin slugs, cell-autonomous differentiation defects, and exclusion
  of mutant cells from the spore mass.
existing_annotations:
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: is_active_in
  review:
    summary: Nuclear localization is correct and is directly supported for DimA,
      which accumulates in the nucleus in response to DIF-1 where it acts as a
      transcription factor.
    action: ACCEPT
    reason: As a bZIP transcription factor DimA acts in the nucleus, consistent with
      direct evidence of DIF-1-induced nuclear accumulation. The phylogenetic
      inference agrees with the experimental data for this gene product.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: upon DIF-1 stimulation, DimA and DimB rapidly accumulate in
        the nucleus
- term:
    id: GO:0010468
    label: regulation of gene expression
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: involved_in
  review:
    summary: DimA regulates the expression of prestalk and prespore genes in
      response to DIF-1, so regulation of gene expression is correct, though it is
      a broad grouping term relative to the more specific transcriptional-regulation
      annotations.
    action: KEEP_AS_NON_CORE
    reason: The term is accurate but general; the more specific regulation of
      DNA-templated transcription (GO:0006355) better captures the core activity.
      Retained as a valid but non-core grouping annotation.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: DimA functions as both an activator of prestalk gene
        expression and repressor of prespore gene expression
- term:
    id: GO:0043565
    label: sequence-specific DNA binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: As a bZIP/bRLZ factor DimA binds DNA sequence-specifically through its
      basic region. This is a core molecular function.
    action: ACCEPT
    reason: DimA is a basic-region leucine-zipper transcription factor; sequence-specific
      DNA binding is intrinsic to this class and is consistent with its role as a
      direct transcriptional regulator of DIF-1 target genes.
    supported_by:
    - reference_id: PMID:14729573
      supporting_text: encodes a bZIP/bRLZ transcription factor, which is
- term:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: enables
  review:
    summary: DimA is a bZIP DNA-binding transcription factor that activates prestalk
      and represses prespore genes; this is a core molecular function.
    action: ACCEPT
    reason: The InterPro bZIP-based inference matches the experimentally established
      role of DimA as a direct transcriptional regulator of DIF-1 responsive genes.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: DimA functions as both an activator of prestalk gene
        expression and repressor of prespore gene expression
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  qualifier: located_in
  review:
    summary: Nuclear localization based on UniProt subcellular location mapping;
      correct and supported by direct evidence of DIF-1-induced nuclear accumulation.
    action: ACCEPT
    reason: The nucleus is the site of DimA action as a transcription factor, and
      DimA accumulates there in response to DIF-1.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: upon DIF-1 stimulation, DimA and DimB rapidly accumulate in
        the nucleus
- term:
    id: GO:0006355
    label: regulation of DNA-templated transcription
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: involved_in
  review:
    summary: DimA directly regulates transcription of DIF-1 target genes, activating
      prestalk and repressing prespore markers. This is a core biological process.
    action: ACCEPT
    reason: Consistent with the experimentally established role of DimA as a direct
      transcriptional regulator downstream of DIF-1.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: DimA functions as both an activator of prestalk gene
        expression and repressor of prespore gene expression
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:16410410
  qualifier: is_active_in
  review:
    summary: Direct evidence that DimA:GFP accumulates in the nucleus upon DIF-1
      stimulation, where it acts as a transcription factor. Core localization.
    action: ACCEPT
    reason: GFP-fusion imaging directly demonstrated rapid, DIF-1-dependent nuclear
      accumulation of DimA, confirming the nucleus as its site of action.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: both DimA:GFP and DimB:GFP exhibited nuclear accumulation
    - reference_id: PMID:16410410
      supporting_text: nuclear accumulation of DimA in response to DIF-1 is dependent
        on DimB
- term:
    id: GO:0031287
    label: positive regulation of sorocarp stalk cell differentiation
  evidence_type: IMP
  original_reference_id: PMID:16410410
  qualifier: involved_in
  review:
    summary: DimA is required for DIF-1-induced prestalk gene induction and stalk-cell
      differentiation; dimA mutant cells fail to induce prestalk markers and do not
      form stalk cells in response to DIF-1.
    action: ACCEPT
    reason: DimA acts as an activator of prestalk gene expression and is required
      for stalk-cell differentiation, a central part of its developmental role.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: DimA functions as both an activator of prestalk gene
        expression and repressor of prespore gene expression
    - reference_id: PMID:16410410
      supporting_text: prestalk markers are not induced and prespore markers are
        not repressed
- term:
    id: GO:0043944
    label: negative regulation of asexual sporulation resulting in formation of a
      cellular spore
  evidence_type: IMP
  original_reference_id: PMID:16410410
  qualifier: involved_in
  review:
    summary: DimA represses the prespore/spore fate in response to DIF-1; spore cell
      formation is repressed by DimA, and dimA mutants fail to repress prespore
      markers.
    action: ACCEPT
    reason: Repression of prespore gene expression and spore formation is a core,
      experimentally established function of DimA downstream of DIF-1.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: spore cell formation is repressed by DimA
    - reference_id: PMID:16410410
      supporting_text: prestalk markers are not induced and prespore markers are
        not repressed
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IDA
  original_reference_id: PMID:16410410
  qualifier: located_in
  review:
    summary: In the absence of DIF-1, DimA:GFP is fairly uniformly distributed
      throughout the cell (including the cytoplasm), redistributing to the nucleus
      upon DIF-1 stimulation. Cytoplasmic localization is thus the resting-state
      distribution rather than the functional site of action.
    action: KEEP_AS_NON_CORE
    reason: The cytoplasmic localization is directly observed but represents the
      unstimulated distribution; the functional site of DimA is the nucleus, so this
      is retained as a non-core annotation.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: In the absence of DIF-1, GFP was fairly uniformly distributed
        throughout the cells
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:16410410
  qualifier: enables
  review:
    summary: This IPI annotation reflects the direct interaction between DimA and
      the related bZIP factor DimB, demonstrated by in vitro pull-down assays. The
      bare protein binding term is uninformative; the more specific dimerization
      activity (with DimB) captures the actual function.
    action: KEEP_AS_NON_CORE
    reason: Protein binding (GO:0005515) is too general to convey function. The
      underlying DimA-DimB heterodimerization is better represented by protein
      dimerization activity, captured in core_functions. Retained as non-core.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: DimA and DimB can form homodimeric and heterodimeric
        complexes in vitro
- term:
    id: GO:0045595
    label: regulation of cell differentiation
  evidence_type: IMP
  original_reference_id: PMID:14729573
  qualifier: involved_in
  review:
    summary: DimA is required to integrate DIF-1 signalling and cell-type
      differentiation; dimA mutants show cell-autonomous defects in cell type
      differentiation. This broad term is correct but subsumed by the more specific
      prestalk/prespore differentiation annotations.
    action: KEEP_AS_NON_CORE
    reason: Accurate but general; the specific roles in stalk-cell differentiation
      and prespore repression are captured by more precise terms. Retained as a
      non-core grouping annotation.
    supported_by:
    - reference_id: PMID:14729573
      supporting_text: the dimA(-) mutant exhibits cell autonomous
- term:
    id: GO:1903013
    label: response to differentiation-inducing factor 1
  evidence_type: IMP
  original_reference_id: PMID:14729573
  qualifier: involved_in
  review:
    summary: DimA is required for every DIF-1 response investigated; the dimA mutant
      produces DIF-1 but cannot respond to it. This is the defining, core function
      of DimA.
    action: ACCEPT
    reason: The response to DIF-1 is the central, experimentally defined role of
      DimA, established by mutant phenotype and by DIF-1-induced nuclear
      accumulation. A core biological process.
    supported_by:
    - reference_id: PMID:14729573
      supporting_text: the dimA(-) mutant produces DIF-1 but
    - reference_id: PMID:16410410
      supporting_text: direct regulators of cellular responses to DIF-1
- term:
    id: GO:0042802
    label: identical protein binding
  evidence_type: IPI
  original_reference_id: PMID:16410410
  qualifier: enables
  review:
    summary: DimA forms homodimeric complexes in vitro, consistent with bZIP factors
      binding DNA as dimers. Identical protein binding (homodimerization) is a
      relevant molecular function.
    action: ACCEPT
    reason: Homodimerization of DimA was directly demonstrated by pull-down assays
      and is functionally important, as bZIP transcription factors bind DNA as
      dimers.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: DimA and DimB can form homodimeric and heterodimeric
        complexes in vitro
- term:
    id: GO:0043565
    label: sequence-specific DNA binding
  evidence_type: IDA
  original_reference_id: PMID:14729573
  qualifier: enables
  review:
    summary: Direct-evidence annotation for sequence-specific DNA binding by the
      bZIP/bRLZ factor DimA. Core molecular function.
    action: ACCEPT
    reason: DimA is a basic-region leucine-zipper DNA-binding transcription factor;
      sequence-specific DNA binding is intrinsic to its function as a direct
      regulator of DIF-1 target genes.
    supported_by:
    - reference_id: PMID:14729573
      supporting_text: encodes a bZIP/bRLZ transcription factor, which is
- term:
    id: GO:0012501
    label: programmed cell death
  evidence_type: IMP
  original_reference_id: PMID:16410410
  qualifier: acts_upstream_of_or_within
  review:
    summary: In the 8-Br-cAMP monolayer assay DimA is proposed to trigger
      non-vacuolar cell death (NVCD) as the first step toward stalk-cell formation,
      linking DimA to a programmed cell death pathway. This is a downstream
      developmental consequence rather than a core molecular activity.
    action: KEEP_AS_NON_CORE
    reason: DimA acts upstream of an NVCD/programmed cell death step during
      stalk-cell differentiation, but this is a peripheral developmental role of the
      transcription factor rather than its core function.
    supported_by:
    - reference_id: PMID:16410410
      supporting_text: The first step would require DimA to trigger NVCD, whereas
        subsequent vacuolisation requires DimB
- term:
    id: GO:0030587
    label: sorocarp development
  evidence_type: IMP
  original_reference_id: PMID:14729573
  qualifier: acts_upstream_of_or_within
  review:
    summary: dimA mutants show hallmark developmental morphological defects (long,
      thin slugs and aberrant culmination) and cell-type differentiation defects,
      placing DimA within sorocarp (fruiting body) development. A broad developmental
      grouping term.
    action: KEEP_AS_NON_CORE
    reason: DimA affects multicellular development through its role in DIF-1 response
      and cell-type patterning; sorocarp development is a correct but broad
      developmental context term, retained as non-core.
    supported_by:
    - reference_id: PMID:14729573
      supporting_text: the dimA(-) mutant exhibits cell autonomous
- term:
    id: GO:0006935
    label: chemotaxis
  evidence_type: IMP
  original_reference_id: PMID:16234315
  qualifier: acts_upstream_of_or_within
  review:
    summary: This annotation derives from a large-scale microarray phenotyping study
      that identified a co-regulated regulon of chemotaxis genes and tested mutants
      for chemotaxis defects. The cached record is abstract-only and does not
      describe dimA specifically, but the dictyBase IMP annotation implies a
      measured chemotaxis phenotype. Chemotaxis is peripheral to DimA's role as a
      DIF-1-responsive transcription factor.
    action: KEEP_AS_NON_CORE
    reason: A chemotaxis phenotype for dimA was inferred from a co-expression/mutant
      phenotyping screen and is a pleiotropic, non-core role relative to DimA's
      central function in DIF-1 signalling and cell-type differentiation.
    supported_by:
    - reference_id: PMID:16234315
      supporting_text: Six mutants exhibited chemotaxis defects
- term:
    id: GO:0030435
    label: sporulation resulting in formation of a cellular spore
  evidence_type: IMP
  original_reference_id: PMID:15470429
  qualifier: acts_upstream_of_or_within
  review:
    summary: In chimaeras, loss of dimA results in exclusion of mutant cells from
      the spore mass, reflecting the pleiotropic linkage between DimA-dependent
      prestalk differentiation and spore formation. DimA thus acts upstream of
      spore formation, but this is a developmental/ecological consequence rather
      than a core molecular function.
    action: KEEP_AS_NON_CORE
    reason: The connection to sporulation is through DimA's role in DIF-1 response
      and cell-fate choice (pleiotropy stabilizing cooperation), not a direct core
      function of the transcription factor. Retained as non-core.
    supported_by:
    - reference_id: PMID:15470429
      supporting_text: lack of the dimA gene results in exclusion from spores
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO
    terms
  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: PMID:14729573
  title: A bZIP/bRLZ transcription factor required for DIF signaling in Dictyostelium.
  findings:
  - statement: dimA encodes a bZIP/bRLZ transcription factor required for every DIF-1
      response investigated.
    supporting_text: encodes a bZIP/bRLZ transcription factor, which is
  - statement: The dimA mutant produces DIF-1 but cannot respond to it, and shows
      cell-autonomous cell-type differentiation defects.
    supporting_text: the dimA(-) mutant produces DIF-1 but
  - statement: DimA is the key transcriptional regulator integrating DIF-1 signalling
      and patterning.
    supporting_text: the key transcriptional regulator required to integrate DIF-1
      signaling
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Primary identification of dimA; abstract-only in cache but the
      abstract directly establishes the bZIP transcription factor identity and the
      DIF-1 response requirement. Experimental (IMP/IDA) annotations rest on the
      full text read by the curator.
- id: PMID:15470429
  title: Pleiotropy as a mechanism to stabilize cooperation.
  findings:
  - statement: dimA is required to receive the DIF-1 signal driving prestalk
      differentiation, and loss of dimA excludes cells from the spore mass.
    supporting_text: lack of the dimA gene results in exclusion from spores
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: Establishes the pleiotropic link between DimA-dependent prestalk
      differentiation and spore formation; supports the acts_upstream_of_or_within
      sporulation annotation as a non-core, developmental role.
- id: PMID:16234315
  title: Microarray phenotyping in Dictyostelium reveals a regulon of chemotaxis genes.
  findings:
  - statement: A co-regulated regulon of chemotaxis genes was identified and mutants
      tested for chemotaxis defects.
    supporting_text: Six mutants exhibited chemotaxis defects
  reference_review:
    relevance: LOW
    correctness: UNVERIFIED
    review_notes: Abstract-only; the abstract does not name dimA. The dictyBase IMP
      chemotaxis annotation implies dimA was among the tested mutants, but the
      specific phenotype cannot be verified from the cached record. Treated as a
      peripheral, non-core role.
- id: PMID:16410410
  title: bZIP transcription factor interactions regulate DIF responses in Dictyostelium.
  findings:
  - statement: DimA and DimB are direct regulators of cellular responses to DIF-1.
    supporting_text: direct regulators of cellular responses to DIF-1
  - statement: DimA functions as both an activator of prestalk gene expression and a
      repressor of prespore gene expression.
    supporting_text: DimA functions as both an activator of prestalk gene expression
      and repressor of prespore gene expression
  - statement: DimA and DimB form homodimeric and heterodimeric complexes in vitro.
    supporting_text: DimA and DimB can form homodimeric and heterodimeric complexes
      in vitro
  - statement: Both DimA and DimB rapidly accumulate in the nucleus upon DIF-1
      stimulation.
    supporting_text: upon DIF-1 stimulation, DimA and DimB rapidly accumulate in the
      nucleus
  - statement: Nuclear accumulation of DimA in response to DIF-1 depends on DimB.
    supporting_text: nuclear accumulation of DimA in response to DIF-1 is dependent
      on DimB
  - statement: Spore cell formation is repressed by DimA.
    supporting_text: spore cell formation is repressed by DimA
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Full-text available and PubMed-verified. Directly supports DimA's
      nuclear localization, DIF-1-induced nuclear accumulation (DimB-dependent),
      homo/heterodimerization with DimB, and activator/repressor roles in prestalk
      vs prespore gene expression.
core_functions:
- description: DimA is a nuclear bZIP/bRLZ DNA-binding transcription factor that
    directly regulates transcription of DIF-1 target genes, activating prestalk
    (pstO) gene expression and repressing prespore gene expression as part of the
    cellular response to the DIF-1 signal.
  molecular_function:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  locations:
  - id: GO:0005634
    label: nucleus
  directly_involved_in:
  - id: GO:1903013
    label: response to differentiation-inducing factor 1
  - id: GO:0006355
    label: regulation of DNA-templated transcription
  supported_by:
  - reference_id: PMID:16410410
    supporting_text: DimA functions as both an activator of prestalk gene expression
      and repressor of prespore gene expression
  - reference_id: PMID:14729573
    supporting_text: encodes a bZIP/bRLZ transcription factor, which is
- description: DimA binds DNA sequence-specifically as a dimer through its basic
    region-leucine zipper, forming homodimers and heterodimers with the related bZIP
    factor DimB; this combinatorial dimerization expands the range of DIF-1 responses
    it can regulate.
  molecular_function:
    id: GO:0046983
    label: protein dimerization activity
  locations:
  - id: GO:0005634
    label: nucleus
  supported_by:
  - reference_id: PMID:16410410
    supporting_text: DimA and DimB can form homodimeric and heterodimeric complexes
      in vitro