MCM8

DNA replication licensing factor MCM8 is a protein that in humans is encoded by the MCM8 gene.^[5][6]

MCM8
Identifiers
Aliases	MCM8, C20orf154, dJ967N21.5, POF10, minichromosome maintenance 8 homologous recombination repair factor
External IDs	OMIM: 608187; MGI: 1913884; HomoloGene: 12001; GeneCards: MCM8; OMA:MCM8 - orthologs
Gene location (Human) Chr. Chromosome 20 (human)[1] Band 20p12.3 Start 5,950,652 bp[1] End 5,998,977 bp[1]
Gene location (Mouse) Chr. Chromosome 2 (mouse)[2] Band 2|2 F2 Start 132,658,061 bp[2] End 132,686,117 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in gonad buccal mucosa cell oocyte testicle secondary oocyte trabecular bone biceps brachii Skeletal muscle tissue of biceps brachii ventricular zone bone marrow cell Top expressed in tail of embryo genital tubercle epiblast hand secondary oocyte embryo zygote ventricular zone embryo primary oocyte More reference expression data BioGPS n/a
Gene ontology Molecular function ATP binding hydrolase activity DNA binding nucleotide binding helicase activity protein binding chromatin binding enzyme binding MutLbeta complex binding MutSalpha complex binding MutSbeta complex binding DNA replication origin binding single-stranded DNA binding Cellular component MCM8-MCM9 complex nucleus nucleoplasm chromosome MCM complex Biological process female gamete generation DNA repair male gamete generation DNA replication cell cycle double-strand break repair via homologous recombination cellular response to DNA damage stimulus DNA replication initiation G1/S transition of mitotic cell cycle recombinational interstrand cross-link repair protein stabilization protein localization to chromatin Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 84515 66634 Ensembl ENSG00000125885 ENSMUSG00000027353 UniProt Q9UJA3 Q9CWV1 RefSeq (mRNA) NM_001281520 NM_001281521 NM_001281522 NM_032485 NM_182802 NM_001291054 NM_025676 RefSeq (protein) NP_001268449 NP_001268450 NP_001268451 NP_115874 NP_877954 NP_001277983 NP_079952 Location (UCSC) Chr 20: 5.95 – 6 Mb Chr 2: 132.66 – 132.69 Mb PubMed search [3] [4]
Wikidata
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The protein encoded by this gene is one of the highly conserved mini-chromosome maintenance proteins (MCM) that are essential for the initiation of eukaryotic genome replication. The hexameric protein complex formed by the MCM proteins is a key component of the pre-replication complex (pre_RC) and may be involved in the formation of replication forks and in the recruitment of other DNA replication related proteins. This protein contains the central domain that is conserved among the MCM proteins. This protein has been shown to co-immunoprecipitate with MCM4, 6 and 7, which suggests that it may interact with other MCM proteins and play a role in DNA replication. Alternatively spliced transcript variants encoding distinct isoforms have been described.^[6]

DNA repair

MCM8-deficient mice are defective in gametogenesis and display genome instability due to impaired homologous recombination.^[7] Male MCM8 (-/-) mice are sterile because spermatocytes are blocked in meiotic prophase I. Female MCM8(-/-) mice have arrested primary follicles and frequently develop ovarian tumors.^[7] MCM8 protein forms a complex with MCM9.

In the plant Arabidopsis thaliana, MCM8 is required for a pathway of meiotic DNA double-strand break repair.^[8] It was proposed that MCM8 is involved with RAD51 in a backup pathway that repairs meiotic double-strand breaks without yielding crossovers when the major recombination pathway, which relies on DMC1, fails.^[8]

A current model of meiotic recombination, initiated by a double-strand break or gap, followed by pairing with an homologous chromosome and strand invasion to initiate the recombinational repair process. Repair of the gap can lead to crossover (CO) or non-crossover (NCO) of the flanking regions. CO recombination is thought to occur by the Double Holliday Junction (DHJ) model, illustrated on the right, above. NCO recombinants are thought to occur primarily by the Synthesis Dependent Strand Annealing (SDSA) model, illustrated on the left, above. Most recombination events appear to be the SDSA type.

MCM8 forms a complex with MCM9 that is required for DNA resection by the MRN complex (MRE11-RAD50-NBS1) at double strand breaks to generate single-stranded DNA ends.^[9] The formation of single-strand ends is an early step in homologous recombination (see Figure). MCM8/MCM9 interacts with MRN and is required for the nuclease action and stable association of MRN with double-strand breaks.^[9]

In humans, an MCM8 mutation can give rise to premature ovarian failure, as well as chromosomal instability.^[10]

See also

• Mini Chromosome Maintenance