José Luís Barbero

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Cohesins, which have been characterized in budding yeast and Xenopus, are multisubunit protein complexes involved in sister chromatid cohesion. Regulation of the interactions among different cohesin subunits and the assembly/disassembly of the cohesin complex to chromatin are key steps in chromosome segregation. We previously characterized the mammalian(More)
We targeted the locus encoding the cyclin-dependent kinase 2 (CDK2) by homologous recombination in mouse embryonic stem (ES) cells. Embryonic fibroblasts lacking CDK2 proliferate normally and become immortal after continuous passage in culture. Elimination of a conditional Cdk2 allele in immortal cells does not have a significant effect on proliferation.(More)
The behavior of meiotic chromosomes differs in several respects from that of their mitotic counterparts, resulting in the generation of genetically distinct haploid cells. This has been attributed in part to a meiosis-specific chromatin-associated protein structure, the synaptonemal complex. This complex consist of two parallel axial elements, each one(More)
BACKGROUND The coordination of cell cycle events is necessary to ensure the proper duplication and dissemination of the genome. In this study, we examine the consequences of depleting Drad21 and SA, two non-SMC subunits of the cohesin complex, by dsRNA-mediated interference in Drosophila cultured cells. RESULTS We have shown that a bona fide cohesin(More)
Cohesins are chromosomal proteins that form complexes involved in the maintenance of sister chromatid cohesion during division of somatic and germ cells. Three meiosis-specific cohesin subunits have been reported in mammals, REC8, STAG3 and SMC1β; their expression in mouse spermatocytes has also been described. Here we studied the localization of different(More)
Shugoshin-2 (SGOL2) is one of the two mammalian orthologs of the Shugoshin/Mei-S322 family of proteins that regulate sister chromatid cohesion by protecting the integrity of the multiprotein cohesin complexes. This protective system is essential for faithful chromosome segregation during mitosis and meiosis, which is the physical basis of Mendelian(More)
The cohesin complex is a ring-shaped proteinaceous structure that entraps the two sister chromatids after replication until the onset of anaphase when the ring is opened by proteolytic cleavage of its α-kleisin subunit (RAD21 at mitosis and REC8 at meiosis) by separase. RAD21L is a recently identified α-kleisin that is present from fish to mammals and(More)
Cohesin is a conserved multisubunit protein complex that participates in chromosome segregation, DNA damage repair, chromatin regulation, and synaptonemal complex (SC) formation. Yeast, but not mice, depleted of the cohesin subunit Rec8 are defective in the formation of the axial elements (AEs) of the SC, suggesting that, in mammals, this function is not(More)
Maintenance and precise regulation of sister chromatid cohesion is essential to ensure correct attachment of chromosomes to the spindle, thus preserving genome integrity by correct chromosome segregation. Errors in these processes often lead to aneuploidy, frequently implicated in cell death and/or tumor development. The so-called cohesin complexes are(More)
Shugoshin (SGO) is a family of proteins that protect centromeric cohesin complexes from release during mitotic prophase and from degradation during meiosis I. Two mammalian SGO paralogues - SGO1 and SGO2 - have been identified, but their distribution and function during mammalian meiosis have not been reported. Here, we analysed the expression of SGO2(More)