Br140 is the Drosophila homolog of the BRPF scaffold proteins (BRPF1/2/3), with PHD-zinc-knuckle-PHD, bromodomain and PWWP chromatin-reader modules. It is the scaffold subunit of the Enok (MOZ/MORF-type) histone acetyltransferase complex, which also contains the catalytic subunit Enok, Ing5 and Eaf6. Br140 is required for the complex's acetylation of histone H3 lysine 23 in vivo and for normal Enok protein levels. Through the Enok complex it associates with the Elg1 PCNA-unloader complex, and the complex promotes the G1/S transition by limiting PCNA unloading from chromatin.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005634 nucleus | EXP PMID:27198229 The Enok acetyltransferase complex interacts with Elg1 and n... | ACCEPT | Summary: Br140 is detected in nuclear fractions. Reason: Correct; consistent across Enok complex subunits. Supporting Evidence: file:DROME/Br140/Br140-uniprot.txt SUBCELLULAR LOCATION: Nucleus |
| GO:0005634 nucleus | IBA GO_REF:0000033 | ACCEPT | Summary: Br140 is nuclear. Reason: Correct; consistent across Enok complex subunits. Supporting Evidence: file:DROME/Br140/Br140-uniprot.txt SUBCELLULAR LOCATION: Nucleus |
| GO:0005634 nucleus | IEA GO_REF:0000044 | ACCEPT | Summary: Br140 is nuclear. Reason: Correct; consistent across Enok complex subunits. Supporting Evidence: file:DROME/Br140/Br140-uniprot.txt SUBCELLULAR LOCATION: Nucleus |
| GO:0006271 DNA strand elongation involved in DNA replication | IDA PMID:27198229 The Enok acetyltransferase complex interacts with Elg1 and n... | MODIFY | Summary: The Enok complex promotes the G1/S transition by restraining Elg1-mediated PCNA unloading. Reason: The study shows a G1/S block and reduced chromatin-bound PCNA after Enok depletion and an Enok complex-Elg1 interaction; it does not measure DNA strand elongation. Replace with GO:0000082 G1/S transition of mitotic cell cycle. Shared complex process treated identically across the four Enok complex subunits. Proposed replacements: G1/S transition of mitotic cell cycle Supporting Evidence: PMID:27198229 Depletion of Enok resulted in an Elg1-dependent block at the G1/S transition and reduced chromatin-bound PCNA levels. |
| GO:0006338 chromatin remodeling | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA for chromatin remodeling (PTN001012887; donors include UniProtKB:P55201 BRPF1, MGI:1926033, SGD:S000006235 and Arabidopsis proteins). Reason: The Enok complex modifies chromatin by H3K23 acetylation; Br140 contributes as scaffold. Plausible but general and not Br140's own activity. |
| GO:0006357 regulation of transcription by RNA polymerase II | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA for regulation of transcription by Pol II (PTN001012887; donors UniProtKB:P55197, MGI:1923539, MGI:1935145, AT2G31650). Reason: Plausible for a HAT-complex scaffold, but no Br140-specific Drosophila evidence on direction or targets; kept non-core at this granularity. |
| GO:0010698 acetyltransferase activator activity | IDA PMID:27198229 The Enok acetyltransferase complex interacts with Elg1 and n... | ACCEPT | Summary: Br140 is required for the Enok complex's H3K23 acetyltransferase activity and for Enok protein levels. Reason: Br140, like BRPF1 for MOZ/MORF, is the scaffold that assembles and stimulates the catalytic subunit; depletion reduces H3K23ac. Shared term treated identically across Br140, Ing5 and Eaf6. Supporting Evidence: PMID:27198229 Depletion of any of the four subunits led to reductions in the H3K23ac levels without affecting the H3K14ac levels PMID:27198229 we concluded that all four subunits are important for full HAT activity of the Enok complex |
| GO:0070776 MOZ/MORF histone acetyltransferase complex | IBA GO_REF:0000033 | ACCEPT | Summary: IBA for MOZ/MORF complex (PTN002674161; donors FB:FBgn0033155 Br140 itself, UniProtKB:O95696 BRD1, P55201 BRPF1, Q9ULD4 BRPF3). Reason: Consistent with direct biochemical evidence in flies. |
| GO:0070776 MOZ/MORF histone acetyltransferase complex | IDA PMID:27198229 The Enok acetyltransferase complex interacts with Elg1 and n... | ACCEPT | Summary: Subunit of the Enok (KAT6, MOZ/MORF-type) acetyltransferase complex. Reason: Core complex. Enok, Br140, Ing5 and Eaf6 co-purify reciprocally and each is required for the complex's H3K23 acetylation; shared complex term treated identically across the four subunits. Supporting Evidence: PMID:27198229 MudPIT analysis of Flag affinity purifications of Flag-HA-tagged Enok, Br140, Eaf6, and Ing5 showed copurification of these four components. |
| GO:0070776 MOZ/MORF histone acetyltransferase complex | IPI PMID:27198229 The Enok acetyltransferase complex interacts with Elg1 and n... | ACCEPT | Summary: Subunit of the Enok (KAT6, MOZ/MORF-type) acetyltransferase complex. Reason: Core complex. Enok, Br140, Ing5 and Eaf6 co-purify reciprocally and each is required for the complex's H3K23 acetylation; shared complex term treated identically across the four subunits. Supporting Evidence: PMID:27198229 MudPIT analysis of Flag affinity purifications of Flag-HA-tagged Enok, Br140, Eaf6, and Ing5 showed copurification of these four components. |
| GO:0140566 histone reader activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA for histone reader activity (PTN001012887; donors UniProtKB:O95696 BRD1, MGI:1924161, SGD:S000006235, ZFIN). Reason: Br140 has the bromodomain, PHD and PWWP reader modules of BRPF proteins; the specific mark(s) read by Br140 in flies have not been determined, so the general term is as precise as warranted. |
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Download this section (compressed HTML)Q: Which histone marks do the Br140 bromodomain, PZP and PWWP modules recognize, and do they target the Enok complex to specific loci such as piRNA clusters?
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Download this section (compressed HTML)Bromodomain-containing protein, 140kD (Br140) encodes a histone acetyltransferase that is a component of the Enok complex, which interacts with the product of elg1 via Br140 to promote the G1/S transition via proliferating cell nuclear antigen (PCNA) unloading.
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