Target genes of the largest human SWI/SNF complex subunit control cell growth.
Target genes of the largest human SWI/SNF complex subunit control cell growth.
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DOI：
10.1042/bj20101358
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发表时间：
2011-02-15
期刊：
影响因子：
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通讯作者：
Tanese N
中科院分区：
文献类型：
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作者：
Inoue H;Giannakopoulos S;Parkhurst CN;Matsumura T;Kono EA;Furukawa T;Tanese N
哺乳动物SWI/SNF-A或BAF（BRG 1相关因子）染色质重塑复合物的最大亚基由两个相关cDNA hOsa 1/BAF 250 a和hOsa 2/BAF 250 b编码，这两个cDNA是BAF复合物所特有的，在相关PBAF（多溴BAF）中不存在。hOsa/BAF 250已显示与转录激活因子相互作用并结合DNA，表明其作用于将重塑复合物靶向染色质。为了更好地了解hOsa 2的功能，我们建立了诱导稳定的HeLa细胞系过表达FLAG-hOsa 2或缺乏ARID（AT丰富的相互作用结构域）DNA结合结构域的衍生物。含有hOsa 2的复合物的免疫纯化，随后通过质谱和免疫印迹证明存在BRG 1和已知的BAF，但不存在hOsa 1或hBRM。删除ARID并没有损害建筑群的完整性。hOsa 2表达的诱导导致受损的细胞生长和积累的细胞在G 0/G1细胞周期阶段。在这些细胞中检测到p53和p21蛋白水平升高，而c-Myc mRNA和蛋白水平降低。染色质免疫沉淀和报告分析表明hOsa 2对c-myc和p21启动子活性有直接影响。因此，hOsa 2在控制调控细胞周期的基因中起重要作用。
The largest subunit of the mammalian SWI/SNF-A or BAF (BRG1-associated factor) chromatin-remodelling complex is encoded by two related cDNAs hOsa1/BAF250a and hOsa2/BAF250b that are unique to the BAF complex and absent in the related PBAF (Polybromo BAF). hOsa/BAF250 has been shown to interact with transcriptional activators and bind to DNA suggesting that it acts to target the remodelling complex to chromatin. To better understand the functions of hOsa2, we established inducible stable HeLa cell lines over-expressing FLAG-hOsa2 or a derivative lacking the ARID (AT-rich interactive domain) DNA-binding domain. Immunopurification of complexes containing hOsa2 that was followed by mass spectrometry and immunoblotting demonstrated the presence of BRG1 and known BAFs, but not hOsa1 or hBRM. Deletion of the ARID did not compromise the integrity of the complex. Induction of hOsa2 expression caused impaired cell growth and accumulation of cells in the G0/G1 cell cycle phase. Elevated levels of the p53 and p21 proteins were detected in these cells while c-Myc mRNA and protein levels were found to decrease. Chromatin immunoprecipitation and reporter assays suggested that hOsa2 had a direct effect on c-myc and p21 promoter activity. Thus hOsa2 plays an important role in controlling genes regulating the cell cycle.