6qnx | pdb_00006qnx
Structure of the SA2/SCC1/CTCF complex
Structural highlights
Disease[RAD21_HUMAN] Cornelia de Lange syndrome. The disease is caused by mutations affecting the gene represented in this entry.[1] Function[STAG2_HUMAN] Component of cohesin complex, a complex required for the cohesion of sister chromatids after DNA replication. The cohesin complex apparently forms a large proteinaceous ring within which sister chromatids can be trapped. At anaphase, the complex is cleaved and dissociates from chromatin, allowing sister chromatids to segregate. The cohesin complex may also play a role in spindle pole assembly during mitosis.[2] [CTCF_HUMAN] Chromatin binding factor that binds to DNA sequence specific sites. Involved in transcriptional regulation by binding to chromatin insulators and preventing interaction between promoter and nearby enhancers and silencers. Acts as transcriptional repressor binding to promoters of vertebrate MYC gene and BAG1 gene. Also binds to the PLK and PIM1 promoters. Acts as a transcriptional activator of APP. Regulates APOA1/C3/A4/A5 gene cluster and controls MHC class II gene expression. Plays an essential role in oocyte and preimplantation embryo development by activating or repressing transcription. Seems to act as tumor suppressor. Plays a critical role in the epigenetic regulation. Participates in the allele-specific gene expression at the imprinted IGF2/H19 gene locus. On the maternal allele, binding within the H19 imprinting control region (ICR) mediates maternally inherited higher-order chromatin conformation to restrict enhancer access to IGF2. Plays a critical role in gene silencing over considerable distances in the genome. Preferentially interacts with unmethylated DNA, preventing spreading of CpG methylation and maintaining methylation-free zones. Inversely, binding to target sites is prevented by CpG methylation. Plays a important role in chromatin remodeling. Can dimerize when it is bound to different DNA sequences, mediating long-range chromatin looping. Mediates interchromosomal association between IGF2/H19 and WSB1/NF1 and may direct distant DNA segments to a common transcription factory. Causes local loss of histone acetylation and gain of histone methylation in the beta-globin locus, without affecting transcription. When bound to chromatin, it provides an anchor point for nucleosomes positioning. Seems to be essential for homologous X-chromosome pairing. May participate with Tsix in establishing a regulatable epigenetic switch for X chromosome inactivation. May play a role in preventing the propagation of stable methylation at the escape genes from X- inactivation. Involved in sister chromatid cohesion. Associates with both centromeres and chromosomal arms during metaphase and required for cohesin localization to CTCF sites. Regulates asynchronous replication of IGF2/H19.[3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [RAD21_HUMAN] Cleavable component of the cohesin complex, involved in chromosome cohesion during cell cycle, in DNA repair, and in apoptosis. The cohesin complex is required for the cohesion of sister chromatids after DNA replication. The cohesin complex apparently forms a large proteinaceous ring within which sister chromatids can be trapped. At metaphase-anaphase transition, this protein is cleaved by separase/ESPL1 and dissociates from chromatin, allowing sister chromatids to segregate. The cohesin complex may also play a role in spindle pole assembly during mitosis. Also plays a role in apoptosis, via its cleavage by caspase-3/CASP3 or caspase-7/CASP7 during early steps of apoptosis: the C-terminal 64 kDa cleavage product may act as a nuclear signal to initiate cytoplasmic events involved in the apoptotic pathway.[13] [14] Publication Abstract from PubMedCohesin catalyses the folding of the genome into loops that are anchored by CTCF(1). The molecular mechanism of how cohesin and CTCF structure the 3D genome has remained unclear. Here we show that a segment within the CTCF N terminus interacts with the SA2-SCC1 subunits of cohesin. A 2.6 A crystal structure of SA2-SCC1 in complex with CTCF reveals the molecular basis of the interaction. We demonstrate that this interaction is specifically required for CTCF-anchored loops and contributes to the positioning of cohesin at CTCF-binding sites. A similar motif is present in a number of established and novel cohesin ligands, including the cohesin release factor WAPL(2,3). Our data suggest that CTCF enables chromatin loop formation by protecting cohesin against loop release. These results provide fundamental insights into the molecular mechanism that enables dynamic regulation of chromatin folding by cohesin and CTCF. The structural basis for cohesin-CTCF-anchored loops.,Li Y, Haarhuis JHI, Cacciatore AS, Oldenkamp R, van Ruiten MS, Willems L, Teunissen H, Muir KW, de Wit E, Rowland BD, Panne D Nature. 2020 Jan 6. pii: 10.1038/s41586-019-1910-z. doi:, 10.1038/s41586-019-1910-z. PMID:31905366[15] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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