A role for BAF57 in cell cycle-dependent transcriptional regulation by the SWI/SNF chromatin remodeling complex.
A role for BAF57 in cell cycle-dependent transcriptional regulation by the SWI/SNF chromatin remodeling complex.
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DOI：
10.1158/0008-5472.can-09-2767
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发表时间：
2010-06-01
期刊：
影响因子：
11.2
通讯作者：
Kraus WL
中科院分区：
文献类型：
--
作者：
Hah N;Kolkman A;Ruhl DD;Pijnappel WW;Heck AJ;Timmers HT;Kraus WL
SWI/SNF复合物是一种ATP依赖的染色质重塑复合物，在基因调控和细胞周期控制中起着关键作用。在本研究中，我们探讨了SWI/SNF的BAF 57亚基通过转录调控细胞周期相关基因在细胞周期调控中的分子功能。我们从稳定表达FLAG标记的BAF 47/BAF 1的HeLa细胞中亲和纯化SWI/SNF，有或没有稳定的shRNA介导的BAF 57敲低。使用基于定量SILAC（细胞培养物中氨基酸的稳定同位素标记）的蛋白质组学方法测定来自这些细胞的全和BAF 57耗尽的SWI/SNF复合物的亚基组成。BAF 57的消耗导致SWI/SNF复合物中BAF 180的显著共消耗，而不降低总细胞BAF 180水平。在SWI/SNF活性的生物化学测定中，holo-和BAF 57/BAF 180-耗尽的SWI/SNF复合物表现出相似的活性。然而，在使用HeLa细胞的细胞增殖测定中，BAF 57的敲低导致细胞在G2/M期的积累、集落形成的抑制和在软琼脂中的生长受损。BAF 57的敲除还引起各种细胞周期相关基因的转录失调，特别是涉及G2晚期的基因。总的来说，我们的研究结果已经确定了BAF 57在SWI/SNF复合物中的新作用，该复合物通过转录调节细胞周期相关基因的子集来维持复合物的适当亚基组成和细胞周期进程。
The SWI/SNF complex is an ATP-dependent chromatin remodeling complex that plays pivotal roles in gene regulation and cell cycle control. In the present study, we explored the molecular functions of the BAF57 subunit of SWI/SNF in cell cycle control via transcription regulation of cell cycle-related genes. We affinity purified SWI/SNF from HeLa cells stably expressing FLAG-tagged BAF47/Ini1 with or without stable shRNA-mediated knockdown of BAF57. The subunit composition of the holo- and BAF57-depleted SWI/SNF complexes from these cells were determined using a quantitative SILAC (Stable Isotope Labeling by Amino Acids in Cell Culture)-based proteomic approach. Depletion of BAF57 resulted in a significant co-depletion of BAF180 from the SWI/SNF complex without decreasing total cellular BAF180 levels. In biochemical assays of SWI/SNF activity, the holo- and BAF57/BAF180-depleted SWI/SNF complexes exhibited similar activities. However, in cell proliferation assays using HeLa cells, knockdown of BAF57 resulted in an accumulation of cells in the G2/M phase, inhibition of colony formation, and impaired growth in soft agar. Knockdown of BAF57 also caused transcriptional misregulation of various cell cycle-related genes, especially genes involved in late G2. Collectively, our results have a identified a new role for BAF57 within the SWI/SNF complex that is required for maintaining the proper subunit composition of the complex and cell cycle progression through the transcriptional regulation of a subset of cell cycle-related genes.