elg1

UniProt ID: Q86BP6
Organism: Drosophila melanogaster
Review Status: COMPLETE
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Gene Description

elg1 encodes the Drosophila ortholog of yeast Elg1 and human ATAD5, the AAA+ large subunit of the Elg1 RFC-like complex, in which it replaces the RFC large subunit and assembles with the four shared small subunits RfC4, RfC38, RfC3 and CG8142. The complex unloads the PCNA sliding clamp from chromatin after DNA replication; depleting elg1 in S2 cells raises chromatin-bound and monoubiquitinated PCNA. The Elg1 complex associates through Br140 with the Enok histone acetyltransferase complex, which restrains PCNA unloading to promote the G1/S transition. In the ovary elg1 is needed for nurse-cell endoreplication, and mutants mislocalize gurken mRNA during oogenesis.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0003677 DNA binding
IBA
GO_REF:0000033 		KEEP AS NON CORE
Summary: DNA binding (IBA).
Reason: PAINT IBA from the RFC large-subunit clade (WITH/FROM FB:FBgn0004913 Gnf1 and RGD:620619 Rfc1). Elg1 shares the AAA+ clamp-loader architecture and is expected to contact DNA within the complex; no more specific DNA-binding term is supported. Peripheral to the core activity, contributes_to GO:0061860 DNA clamp unloader activity.
GO:0005634 nucleus
EXP
PMID:27198229
The Enok acetyltransferase complex interacts with Elg1 and n... 		ACCEPT
Summary: Nucleus.
Reason: Elg1 acts on chromatin-bound PCNA in the nucleus; nuclear localization is recorded by UniProt from PMID:27198229.
Supporting Evidence:
file:DROME/elg1/elg1-uniprot.txt
SUBCELLULAR LOCATION: Nucleus {ECO:0000269|PubMed:27198229}
GO:0005634 nucleus
IBA
GO_REF:0000033 		ACCEPT
Summary: Nucleus.
Reason: Elg1 acts on chromatin-bound PCNA in the nucleus; nuclear localization is recorded by UniProt from PMID:27198229.
Supporting Evidence:
file:DROME/elg1/elg1-uniprot.txt
SUBCELLULAR LOCATION: Nucleus {ECO:0000269|PubMed:27198229}
GO:0005634 nucleus
IEA
GO_REF:0000044 		ACCEPT
Summary: Nucleus.
Reason: Elg1 acts on chromatin-bound PCNA in the nucleus; nuclear localization is recorded by UniProt from PMID:27198229.
Supporting Evidence:
file:DROME/elg1/elg1-uniprot.txt
SUBCELLULAR LOCATION: Nucleus {ECO:0000269|PubMed:27198229}
GO:0005634 nucleus
NAS
PMID:24204884
The elongin complex antagonizes the chromatin factor Corto f... 		ACCEPT
Summary: Nucleus.
Reason: Elg1 acts on chromatin-bound PCNA in the nucleus; nuclear localization is recorded by UniProt from PMID:27198229.
Supporting Evidence:
file:DROME/elg1/elg1-uniprot.txt
SUBCELLULAR LOCATION: Nucleus {ECO:0000269|PubMed:27198229}
GO:0006271 DNA strand elongation involved in DNA replication
NAS
PMID:24204884
The elongin complex antagonizes the chromatin factor Corto f... 		MODIFY
Summary: DNA strand elongation involved in DNA replication (NAS).
Reason: The cited paper (PMID:24204884) concerns Elongin/Corto and does not discuss Elg1. Elg1 does not load PCNA for strand elongation; it removes PCNA after Okazaki fragment ligation, i.e. it acts in DNA replication but after elongation. The replication role is sound, so the term is generalized to GO:0006261 DNA-templated DNA replication.
Proposed replacements: DNA-templated DNA replication
Supporting Evidence:
PMID:27198229
knocking down elg1 using dsRNAs did not affect total PCNA levels but resulted in increases in the levels of both chromatin-bound PCNA and monoubiquitinated PCNA
GO:0031391 Elg1 RFC-like complex
IDA
PMID:27198229
The Enok acetyltransferase complex interacts with Elg1 and n... 		ACCEPT
Summary: Large subunit of the Elg1 RFC-like complex.
Reason: Affinity purification of Flag-Elg1 and Flag-Br140 recovered Elg1 with all four RFC small subunits. For the IPI row, the cited PMID:24204884 does not mention Elg1, but complex membership is directly supported by PMID:27198229.
Supporting Evidence:
PMID:27198229
identified peptides from all components of the Elg1 PCNA-unloader complex: Elg1, Rfc4, Rfc38, CG8142, and Rfc3
GO:0031391 Elg1 RFC-like complex
IPI
PMID:24204884
The elongin complex antagonizes the chromatin factor Corto f... 		ACCEPT
Summary: Large subunit of the Elg1 RFC-like complex.
Reason: Affinity purification of Flag-Elg1 and Flag-Br140 recovered Elg1 with all four RFC small subunits. For the IPI row, the cited PMID:24204884 does not mention Elg1, but complex membership is directly supported by PMID:27198229.
Supporting Evidence:
PMID:27198229
identified peptides from all components of the Elg1 PCNA-unloader complex: Elg1, Rfc4, Rfc38, CG8142, and Rfc3
GO:0048477 oogenesis
IMP
PMID:24531791
A genetic screen based on in vivo RNA imaging reveals centro... 		KEEP AS NON CORE
Summary: Oogenesis (IMP).
Reason: elg1 mutants from an ovarian screen mislocalize grk mRNA and fail in nurse-cell endoreplication; this is a downstream developmental consequence of defective PCNA cycling in the endocycling germline rather than a direct role.
Supporting Evidence:
PMID:24531791
elg1 is required for grk transcript localization and nurse cell endoreplication
PMID:27198229
knocking down enok partially rescued the defective nurse cell endoreplication observed in the Elg1-depleted germline
GO:0061860 DNA clamp unloader activity
IBA
GO_REF:0000033 		ACCEPT
Summary: DNA clamp (PCNA) unloader activity of the Elg1 RFC-like complex.
Reason: PAINT IBA seeded by human ATAD5 (UniProtKB:Q96QE3), whose complex unloads PCNA from chromatin. Drosophila evidence agrees: elg1 RNAi raises chromatin-bound and monoubiquitinated PCNA without changing total PCNA. The activity is exerted by the Elg1 heteropentamer, so in core_functions it is recorded as contributes_to with the complex.
Supporting Evidence:
PMID:27198229
knocking down elg1 using dsRNAs did not affect total PCNA levels but resulted in increases in the levels of both chromatin-bound PCNA and monoubiquitinated PCNA
file:DROME/elg1/elg1-uniprot.txt
regulates the functions of the DNA polymerase processivity factor PCNA by unloading it from DNA after replication during the S phase of the cell cycle
file:DROME/elg1/elg1-deep-research-falcon.md
In experimentally characterized Elg1/ATAD5 complexes, Elg1 or ATAD5 takes the place of the large canonical RFC1 subunit alongside the four smaller RFC subunits

Core Functions

Elg1 is the large subunit of the Elg1 RFC-like complex, which removes PCNA from DNA after replication, limiting the chromatin-bound and monoubiquitinated PCNA pool.

Directly Involved In:
DNA-templated DNA replication
Cellular Locations:
nucleus
In Complex:
Elg1 RFC-like complex
Supporting Evidence:
  • PMID:27198229
    knocking down elg1 using dsRNAs did not affect total PCNA levels but resulted in increases in the levels of both chromatin-bound PCNA and monoubiquitinated PCNA
  • PMID:27198229
    identified peptides from all components of the Elg1 PCNA-unloader complex: Elg1, Rfc4, Rfc38, CG8142, and Rfc3

References

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Suggested Questions for Experts

Q: Does Drosophila Elg1 promote PCNA deubiquitination directly (as ATAD5 does with USP1-UAF1), or is the rise in PCNA-ub after elg1 RNAi a secondary consequence of PCNA retention on chromatin?

Q: How does the Br140-mediated contact with the Enok complex inhibit Elg1-dependent PCNA unloading mechanistically?

Suggested Experiments

Experiment: Reconstitute the Drosophila Elg1 RFC-like complex and test ATP-dependent PCNA unloading in vitro, with and without the Enok complex or Br140.

Deep Research

Falcon

(elg1-deep-research-falcon.md)

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📚 Additional Documentation

Notes

(elg1-notes.md)

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📄 View Raw YAML

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