mcm-4 (C. elegans) review notes

Identity

Core function (well established)

mcm-4 encodes the C. elegans ortholog of MCM4, a subunit of the heterohexameric
MCM2-7 pre-replication complex / replicative helicase. As part of the CMG
(CDC45–MCM–GINS) helicase it unwinds template DNA during S-phase. Conserved
roles: replication licensing, DNA synthesis (elongation), and the DNA replication
checkpoint coupling M-phase entry to S-phase completion.

Key evidence from cached publications

PMID:21146520 (Korzelius et al., 2011, Dev Biol) — full text available, PRIMARY

PMID:31283754 (Wang et al., 2019, PLoS Genet) — full text available, PRIMARY

PMID:7262539 (Sulston & Horvitz, 1981, Genetics) — ABSTRACT ONLY (no full text)

Annotation triage summary (pre-agent)

Deep research status

Falcon deep research (just deep-research-falcon worm mcm-4 --fallback perplexity-lite)
was launched in parallel with publication caching. The wrapper reported a 600s timeout
(and the perplexity-lite fallback was unavailable in this environment), but falcon in
fact completed after ~1406s and wrote mcm-4-deep-research-falcon.md (51 citations) plus
artifacts. The report corroborates the entire review: it confirms the
lin-6/let-358 = mcm-4 = MCM4 identity, the complex-level ATPase/helicase activities
(incl. the MCM4/6/7 subcomplex biochemistry), the replication checkpoint role, the
epidermis-specific requirement, and the nuclear→diffuse(NEBD)→late-anaphase chromatin
localization dynamics. No annotation decision needed changing.

New context (not annotation-changing): a 2024 study (Memar et al., Nat Commun) reports a
replication-independent role for the CMG helicase in asymmetric cell-fate divergence
(via the GINS subunit PSF-2, not mcm-4 directly), proposed to act through
chromatin/histone handling at the egl-1 locus. Captured as a new suggested_question and
noted in the deep-research reference_review; MCM-4's strongest evidence remains canonical
licensing/helicase. The deep-research file is now cited (additional_reference_ids +
supported_by) on the ssDNA helicase activity annotation.

Thorough integration pass (follow-up)

Wove the deep-research findings into the relevant annotations beyond the single
ssDNA-helicase citation:
- DNA helicase activity (GO:0003678, IEA) and ATP hydrolysis (GO:0016887, IEA): added
the MCM4/6/7 subcomplex biochemistry (intrinsic ssDNA-dependent ATP hydrolysis;
ATPase/helicase with ATP hydrolysis in the MCM ring driving translocation/unwinding).
- nucleus (GO:0005634, IDA) and chromosome (GO:0005694, EXP): added the cell-cycle
localization dynamics (nuclear interphase → diffuse at NEBD → not on metaphase
chromatin → reassociates in late anaphase).
- Added Ruijtenberg, van den Heuvel & The 2011 (doi:10.5772/19397) to references,
surfaced by deep research; marked correctness=UNVERIFIED because it has no PMID, is
not in the GOA, and was not independently retrieved/read in this review.
All deep-research supporting_text quotes validate against the cached report.

PR #1514 review fix: protein binding (GO:0005515, IPI)

Reviewer correctly flagged that the original supporting_text quoted the NMAD-1/TOP-2
in vivo co-IP and the summary wrongly implied MCM-4 co-IP. Verified from PMID:31283754
full text:
- MCM-4 identified in NMAD-1 IP/MS as a candidate binder.
- NMAD-1 binds MCM-4 directly in vitro (recombinant His-NMAD-1 pulldown of MCM-4;
Fig 4B / S5). PMID:31283754
- In vivo interaction with MCM-4 was not confirmed; only NMAD-1/TOP-2 confirmed in
vivo. PMID:31283754
Corrected the annotation summary/reason and supporting_text accordingly (in vitro direct
binding cited; in vivo caveat stated), and refined the PMID:31283754 reference finding.
Action remains KEEP_AS_NON_CORE (uninformative MF term; in vitro direct binding still
supports the IPI).