Purification and biochemical heterogeneity of the mammalian SWI-SNF complex
Purification and biochemical heterogeneity of the mammalian SWI-SNF complex
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DOI：
10.1002/j.1460-2075.1996.tb00921.x
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发表时间：
1996-10-01
期刊：
影响因子：
11.4
通讯作者：
Crabtree, GR
中科院分区：
文献类型：
--
作者：
Wang, WD;Cote, J;Crabtree, GR
我们使用SWI 2-SNF 2同源物BRG 1的抗体从几种哺乳动物细胞系中纯化了9至12种蛋白质[称为BRG 1相关因子（BAF）]的不同复合物。微测序显示47 kDa BAF与INI 1相同。以前已显示INI 1与人免疫缺陷病毒整合酶相互作用并激活，与酵母SNF 5基因同源，用抗INI 1/BAF 47的抗体亲和纯化一组BAF 47相关蛋白，发现与用BRG 1共纯化的那些相同，强烈表明该组蛋白紧密结合，可能是酵母SWI-SNF复合物的哺乳动物等同物，含有BRG 1的复合物可以破坏核小体并促进GAL 4-VP 16与核小体模板的结合，类似于酵母SWI-SNF复合物，从几种细胞系中纯化复合物表明，它在亚基组成方面是异质的。在单独的复合物中发现了两种SWI-SNF 2同源物，BRG 1和hbrm，某些细胞系完全缺乏BRG 1和hbrm，表明它们不是细胞生存力所必需的，并且哺乳动物SWI-SNF复合物可被定制以适应分化细胞类型的需要。
We have purified distinct complexes of nine to 12 proteins [referred to as BRG1-associated factors (BAFs)] from several mammalian cell lines using an antibody to the SWI2-SNF2 homolog BRG1, Microsequencing revealed that the 47 kDa BAF is identical to INI1, Previously INI1 has been shown to interact with and activate human immunodeficiency virus integrase and to be homologous to the yeast SNF5 gene, A group of BAF47-associated proteins were affinity purified with antibodies against INI1/BAF47 and were found to be identical to those co-purified with BRG1, strongly indicating that this group of proteins associates tightly and is likely to be the mammalian equivalent of the yeast SWI-SNF complex, Complexes containing BRG1 can disrupt nucleosomes and facilitate the binding of GAL4-VP16 to a nucleosomal template similar to the yeast SWI-SNF complex, Purification of the complex from several cell lines demonstrates that it is heterogeneous with respect to subunit composition, The two SWI-SNF2 homologs, BRG1 and hbrm, were found in separate complexes, Certain cell lines completely lack BRG1 and hbrm, indicating that they are not essential for cell viability and that the mammalian SWI-SNF complex mag be tailored to the needs of a differentiated cell type.