Expansion of chromosome territories with chromatin decompaction in BAF53-depleted interphase cells.
Chromosomes are compartmentalized into discrete chromosome territories during interphase in mammalian cells. A chromosome territory is generated by the tendency of chromatin to occupy the smallest shell volume, which is determined by the polymeric properties and interactions of the internal meshwork of the chromatin fiber. Here, we show that BAF53 knockdown by small interfering RNA interference led to the expansion of chromosome territories. This was accompanied by a reduction in chromatin compaction, an increase in the micrococcal nuclease sensitivity of the chromatin, and an alteration in H3-K9 and H3-K79 dimethylation. Interestingly, the BAF53 knockdown cells suffer a cell cycle defect. Despite the significant irregularity and decompaction of the polynucleosomes isolated from the BAF53 knockdown cells, the chromatin loading of H1 and core histones remained unaltered, as did the nucleosome spacing. The histone hyperacetylation and down-regulation of BRG-1, mBrm, and Tip49, the catalytic components of the SWI/SNF complex and the TIP60 complex, respectively, did not expand chromosome territories. These results indicate that BAF53 contributes to the polymeric properties and/or the internal meshwork interactions of the chromatin fiber probably via a novel mechanism.
Lee
Kiwon
K
Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yongin 449-791, Korea.
Kang
Mi Jin
MJ
Kwon
Su Jin
SJ
Kwon
Yunhee Kim
YK
Kim
Ki Woo
KW
Lim
Jae-Hwan
JH
Kwon
Hyockman
H
D000107:Acetylation; D000199:Actins / Q000172:deficiency*; D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000172:deficiency*; D033481:Chromosomes, Mammalian / Q000378:metabolism*; D004265:DNA Helicases / Q000235:genetics; D004268:DNA-Binding Proteins / Q000172:deficiency*; D015536:Down-Regulation / Q000235:genetics; D006657:Histones / Q000378:metabolism; D007399:Interphase; D008239:Lysine / Q000378:metabolism; D008745:Methylation; D051379:Mice; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000235:genetics; D009707:Nucleosomes / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics
D000199:Actins; C485486:Actl6a protein, mouse; D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D006657:Histones; D009687:Nuclear Proteins; D009707:Nucleosomes; C499503:Smarca2 protein, mouse; D014157:Transcription Factors; C513194:Smarca4 protein, mouse; D004265:DNA Helicases; D008239:Lysine