Identification and characterization of SA/Scc3p subunits in the Xenopus and human cohesin complexes

Losada, A., Yokochi, T., Kobayashi, R., Hirano, T. (August 2000) Identification and characterization of SA/Scc3p subunits in the Xenopus and human cohesin complexes. Journal of Cell Biology, 150 (3). pp. 405-416. ISSN 0021-9525

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Abstract

A multisubunit protein complex, termed cohesin. plays an essential role in sister chromatid cohesion in yeast and in Xenopus laevis cell-free extracts. We report here that two distinct cohesin complexes exist in Xenopus egg extracts. A 14S complex (x-cohesin(SA1)) contains XSMC1, XSMC3, XRAD21, and a newly identified subunit, XSA1, In a second 12.5S complex (x-cohesin(SA2)), XSMC1, XSMC3, and XRAD21 associate with a different subunit, XSA2. Both XSA1 and XSA2 belong to the SA family of mammalian proteins and exhibit similarity to Scc3p, a recently identified component of yeast cohesin. In Xenopus egg extracts, x-cohesin(SA1) is predominant, whereas x-cohesinSA2 constitutes only a very minor population. Human cells have a similar pair of cohesin complexes, but the SA2-type is the dominant form in somatic tissue culture cells. Immunolocalization experiments suggest that chromatin association of cohesin(SA1) and cohesin(SA2) may be differentially regulated. Dissociation of x-cohesin(SA1) from chromatin correlates with phosphorylation of XSA1 in the cell-free extracts. Purified cdc2-cyclin B can phosphorylate XSA1 in vitro and reduce the ability of x-cohesin(SA1) to bind to DNA or chromatin, These results shed light on the mechanism by which sister chromatid cohesion is partially dissolved in early mitosis, far before the onset of anaphase, in vertebrate cells.

Item Type: Paper
Uncontrolled Keywords: Xenopus egg extract sister chromatid cohesion SMC proteins chromosome structure mitosis SISTER-CHROMATID COHESION SCHIZOSACCHAROMYCES-POMBE CHROMOSOME CONDENSATION PROTEIN COMPLEXES DNA-REPLICATION FISSION YEAST 13S CONDENSIN CELL-CYCLE IN-VITRO MEIOSIS
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > cohesin
organism description > animal > mammal > primates > hominids > human
organism description > animal > Frog > xenopus
CSHL Authors:
Communities: CSHL labs > Hirano lab
CSHL labs > Kobayashi lab
Depositing User: Matt Covey
Date: August 2000
Date Deposited: 30 Jan 2014 16:25
Last Modified: 30 Jan 2014 16:25
PMCID: PMC2175199
Related URLs:
URI: https://repository.cshl.edu/id/eprint/29402

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