The Adenomatous Polyposis Coli protein contributes to normal compaction of mitotic chromatin

Dikovskaya, D., Khoudoli, G., Newton, I.P., Chadha, G.S., Klotz, D., Visvanathan, A., Lamond, A., Swedlow, J.R. and Näthke, I.S. (2012) The Adenomatous Polyposis Coli protein contributes to normal compaction of mitotic chromatin. PLoS ONE, 7(6), e38102. (doi: 10.1371/journal.pone.0038102)

Abstract

The tumour suppressor <i>Adenomatous Polyposis Coli</i> (APC) is required for proper mitosis; however, the exact role of APC in mitosis is not understood. Using demembranated sperm chromatin exposed to meiotic <i>Xenopus</i> egg extract and HeLa cells expressing fluorescently labelled histones, we established that APC contributes to chromatin compaction. Sperm chromatin in APC-depleted <i>Xenopus</i> egg extract frequently formed tight round or elongated structures. Such abnormally compacted chromatin predominantly formed spindles with low microtubule content. Furthermore, in mitotic HeLa cells expressing GFP- and mCherry-labelled H2B histones, depletion of APC caused a decrease in the donor fluorescence lifetime of neighbouring fluorophores, indicative of excessive chromatin compaction. Profiling the chromatin-associated proteome of sperm chromatin incubated with <i>Xenopus</i> egg extracts revealed temporal APC-dependent changes in the abundance of histones, closely mirrored by chromatin-associated Topoisomerase IIa, condensin I complex and Kif4. In the absence of APC these factors initially accumulated on chromatin, but then decreased faster than in controls. We also found and validated significant APC-dependent changes in chromatin modifiers Set-a and Rbbp7. Both were decreased on chromatin in APC-depleted extract; in addition, the kinetics of association of Set-a with chromatin was altered in the absence of APC.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Dikovskaya, Dr Dina
• Authors: Dikovskaya, D., Khoudoli, G., Newton, I.P., Chadha, G.S., Klotz, D., Visvanathan, A., Lamond, A., Swedlow, J.R., and Näthke, I.S.
• College/School: College of Medical Veterinary and Life Sciences > School of Cancer Sciences
• Journal Name: PLoS ONE
• Publisher: Public Library of Science
• ISSN: 1932-6203
• Published Online: 13 June 2012
• Copyright Holders: Copyright © 2012 The Authors
• First Published: First published in PLoS ONE 7(6):e38102
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher