ISWI remodeling complexes in Xenopus egg extracts: Identification as major chromosomal components that are regulated by INCENP-aurora B

MacCallum, D. E., Losada, A., Kobayashi, R., Hirano, T. (January 2002) ISWI remodeling complexes in Xenopus egg extracts: Identification as major chromosomal components that are regulated by INCENP-aurora B. Molecular Biology of the Cell, 13 (1). pp. 25-39. ISSN 1059-1524

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Abstract

We previously characterized major components of mitotic chromosomes assembled in Xenopus laevis egg extracts and collectively referred to them as Xenopuschromosome–associated polypeptides (XCAPs). They included five subunits of the condensin complex essential for chromosome condensation. In an effort to identify novel proteins involved in this process, we have isolated XCAP-F and found it to be theXenopus ortholog of ISWI, a chromatin remodeling ATPase. ISWI exists in two major complexes in Xenopus egg extracts. The first complex contains ACF1 and two low-molecular-weight subunits, most likely corresponding to Xenopus CHRAC. The second complex is a novel one that contains theXenopus ortholog of the human Williams syndrome transcription factor (WSTF). In the absence of the ISWI complexes, the deposition of histones onto DNA is apparently normal, but the spacing of nucleosomes is greatly disturbed. Despite the poor spacing of nucleosomes, ISWI depletion has little effect on DNA replication, chromosome condensation or sister chromatid cohesion in the cell-free extracts. The association of ISWI with chromatin is cell cycle regulated and is under the control of the INCENP-aurora B kinase complex that phosphorylates histone H3 during mitosis. Apparently contradictory to the generally accepted model, we find that neither chromosome condensation nor chromosomal targeting of condensin is compromised when H3 phosphorylation is drastically reduced by depletion of INCENP-aurora B.

Item Type: Paper
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > chromosome
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > chromosomes, structure and function > chromosome
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > chromosomes, structure and function
organism description > animal > Frog > xenopus
CSHL Authors:
Communities: CSHL labs > Hirano lab
CSHL labs > Kobayashi lab
Depositing User: Matt Covey
Date: January 2002
Date Deposited: 08 Jan 2014 16:27
Last Modified: 08 Jan 2014 16:27
PMCID: PMC65070
Related URLs:
URI: https://repository.cshl.edu/id/eprint/28741

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