title: The specific contributions of cohesin-SA1 to cohesion and gene expression: implications for cancer and development.
abstract: Besides its well-established role in sister chromatid cohesion, cohesin has recently emerged as major player in the organization of interphase chromatin. Such important function is related to its ability to entrap two DNA segments also in cis, thereby facilitating long-range DNA looping which is crucial for transcriptional regulation, organization of replication factories and V(D)J recombination. Vertebrate somatic cells have two different versions of cohesin, containing Smc1, Smc3, Rad21/Scc1 and either SA1 or SA2, but their functional specificity has been largely ignored. We recently generated a knockout mouse model for the gene encoding SA1, and found that this protein is essential to complete embryonic development. Cohesin-SA1 mediates cohesion at telomeres, which is required for their replication. Telomere defects in SA1- deficient cells provoke chromosome segregation errors resulting in aneuploidy despite robust centromere cohesion. This aneuploidy could explain why heterozygous animals have an earlier onset of tumorigenesis. In addition, the genome-wide distribution of cohesin changes dramatically in the absence of SA1, and the complex shows reduced accumulation at promoters and CTCF sites. As a consequence, gene expression is altered, leading to downregulation of biological processes related to a developmental disorder linked to cohesin function, the Cornelia de Lange Syndrome (CdLS). These results point out a prominent role of cohesin-SA1 in transcriptional regulation, with clear implications in the etiology of CdLS.
authors.affiliation: Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre, Madrid, Spain. acuadrado@cnio.es
authors.forename: Ana
authors.initials: A
authors.lastname: Cuadrado
authors.forename: Silvia
authors.initials: S
authors.lastname: Remeseiro
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Gómez-López
authors.forename: David G
authors.initials: DG
authors.lastname: Pisano
authors.forename: Ana
authors.initials: A
authors.lastname: Losada
mesh_terms: D026924:Amino Acid Transport System A / Q000235:genetics / Q000378:metabolism*; D000782:Aneuploidy; D000818:Animals; D001665:Binding Sites; D000076246:CCCTC-Binding Factor; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002471:Cell Transformation, Neoplastic; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D020090:Chromosome Segregation; D003635:De Lange Syndrome / Q000209:etiology; D047108:Embryonic Development; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000378:metabolism; D016615:Telomere / Q000378:metabolism; D000097722:Cohesins
chemical_list: D026924:Amino Acid Transport System A; D000076246:CCCTC-Binding Factor; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D012097:Repressor Proteins; D000097722:Cohesins; C000619697:CTCF protein, human; C000619698:Ctcf protein, mouse