GMNN
Description
The GMNN (geminin DNA replication inhibitor) is a protein-coding gene located on chromosome 6.
Geminin, DNA replication inhibitor, also known as GMNN, is a protein in humans encoded by the GMNN gene. A nuclear protein present in most eukaryotes and highly conserved across species, numerous functions have been elucidated for geminin including roles in metazoan cell cycle, cellular proliferation, cell lineage commitment, and neural differentiation. One example of its function is the inhibition of Cdt1.
== History == Geminin was originally identified as an inhibitor of DNA replication and substrate of the anaphase-promoting complex. Coincidentally, geminin was also shown to expand the neural plate in the developing Xenopus embryo.
== Structure == Geminin is a nuclear protein made up of about 200 amino acids, with a molecular weight of approximately 25 kDa. It contains an atypical leucine zipper coiled-coil domain. It has no known enzymatic activity nor DNA binding motifs.
== Function ==
=== Cell cycle control === Geminin is absent during G1 phase and accumulates through S, G2 phase and M phases of the cell cycle. Geminin levels drop at the metaphase-anaphase transition of mitosis when it is degraded by the anaphase-promoting complex.
Inhibits DNA replication by preventing the incorporation of MCM complex into pre-replication complex (pre-RC) (PubMed:9635433, PubMed:14993212, PubMed:20129055, PubMed:24064211). It is degraded during the mitotic phase of the cell cycle (PubMed:9635433, PubMed:14993212, PubMed:24064211). Its destruction at the metaphase-anaphase transition permits replication in the succeeding cell cycle (PubMed:9635433, PubMed:14993212, PubMed:24064211). Inhibits histone acetyltransferase activity of KAT7/HBO1 in a CDT1-dependent manner, inhibiting histone H4 acetylation and DNA replication licensing (PubMed:20129055). Inhibits the transcriptional activity of a subset of Hox proteins, enrolling them in cell proliferative control (PubMed:22615398). {ECO:0000269|PubMed:14993212, ECO:0000269|PubMed:20129055, ECO:0000269|PubMed:22615398, ECO:0000269|PubMed:24064211, ECO:0000269|PubMed:9635433}
GMNN is also known as Gem, MGORS6.
