SMC1B
Protein-coding gene in the species Homo sapiens
From Wikipedia, the free encyclopedia
Structural maintenance of chromosomes protein 1B (SMC-1B) is a protein that in humans is encoded by the SMC1B gene.[5][6][7] SMC proteins engage in chromosome organization and can be broken into 3 groups based on function which are cohesins, condensins, and DNA repair.[8][9][10] SMC-1B belongs to a family of proteins required for chromatid cohesion and DNA recombination during meiosis and mitosis.[7][11] SMC1B protein appears to participate with other cohesins REC8, STAG3 and SMC3 in sister-chromatid cohesion throughout the whole meiotic process in human oocytes.[12]
| SMC1B | |||||||||||||||||||||||||||||||||||||||||||||||||||
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| Aliases | SMC1B, SMC1BETA, SMC1L2, structural maintenance of chromosomes 1B | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | OMIM: 608685; MGI: 2154049; HomoloGene: 13786; GeneCards: SMC1B; OMA:SMC1B - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Function
SMC1B is essential for meiosis in which it has 3 main roles.[13] SMC1B is known to be involved in the fusion of chromosomes during meiosis in both homologous and non-homologous chromosomes.[13] SMC1B develops the axial elements (AE) found in synaptonemal complexes in association with other cohesin proteins REC8 and SMC3 as well as AE proteins SCP2 and SCP3.[14][15] Sister chromatid cohesion in meiosis is supplied by SMC1B.[13] SMC1B can also protect telomeres from damage, something that SMC1A has not been shown to be capable of.[16] Additionally, in somatic cells SMC1B associates with SMC3 and RAD21 in a mitotic cohesin complex which had been thought to only include SMC1α.[17][18] Depletion of SMC1B in somatic cells showed dysregulation of some gene expression.[17]
Clinical Significance
Human Papillomavirus (HPV)
Human Papillomavirus (HPV) is a DNA virus and the most prevalent sexually transmitted infection.[19] HPV-16 and HPV-18 are responsible for most cases of cervical cancer from HPV.[20] SMC1B has increased expression in HPV(+) cases.[21] HPV recruits SMC1 along with a transcriptional factor, CTCF, to enable replication of the virus's genome. SMC1 is crucially important to the regulation of the virus life cycle.[20]
Genome Instability and Cancer
SMC1B protects genetic stability from ultraviolet and infrared radiation.[18] Altered expression of SMC1B can cause DNA damage repair to fail that then causes genome instability.[18] Expression of SMC1B higher or lower than normal is associated with certain cancers. Meiotic subunits STAG3 and REC8 are also expressed with SMC1B in cancers.[22] High expression of SMC1B can be associated with pancreatic cancers and ovarian cancer, while low expression increases the risk of cancer progression due to low genetic stability.[18]