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XB-ART-45454
PLoS One January 1, 2012; 7 (6): e38102.
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The adenomatous polyposis coli protein contributes to normal compaction of mitotic chromatin.

Dikovskaya D , Khoudoli G , Newton IP , Chadha GS , Klotz D , Visvanathan A , Lamond A , Swedlow JR , Näthke IS .


Abstract
The tumour suppressor Adenomatous Polyposis Coli (APC) is required for proper mitosis; however, the exact role of APC in mitosis is not understood. Using demembranated sperm chromatin exposed to meiotic Xenopus egg extract and HeLa cells expressing fluorescently labelled histones, we established that APC contributes to chromatin compaction. Sperm chromatin in APC-depleted Xenopus 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 Xenopus 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.

PubMed ID: 22719865
PMC ID: PMC3374815
Article link: PLoS One
Grant support: [+]

Species referenced: Xenopus
Genes referenced: h2ac21 h2bc21 rbbp7 set smc2


Article Images: [+] show captions
References [+] :
Adachi, Chromosome assembly in vitro: topoisomerase II is required for condensation. 1991, Pubmed, Xenbase