Reconstitution of glucocorticoid receptor-dependent transcription in vivo
Reconstitution of glucocorticoid receptor-dependent transcription in vivo
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DOI：
10.1128/mcb.24.8.3347-3358.2004
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发表时间：
2004-04-01
影响因子：
5.3
通讯作者：
Archer, TK
中科院分区：
文献类型：
--
作者：
Trotter, KW;Archer, TK
我们开发了一个模型系统来研究糖皮质激素受体（GR）介导的染色质重塑的BRG 1复合物。将BRG 1 ATP酶导入SW-13细胞系中可启动功能性重塑复合物的形成。该复合物能够诱导转录激活从瞬时转染的启动子与野生型和染色质重塑缺陷型BRG 1突变体，这表明该复合物具有辅激活因子的功能，独立于重塑。来自染色质模板的反式激活需要BRG 1重塑功能，其诱导超敏反应区域和转录因子加载到整合的MMTV启动子上。我们报告说，BRG 1重塑活动所需的GR介导的反式激活，这种活动不能被其他ATP依赖性重塑蛋白所取代。对这些细胞中存在的BRG 1相关因子（BAF）的进一步表征（例如，表达BAF 250，但不表达BAF 180）表明，BAF复合物而不是多溴相关BAF复合物是受体在体内发挥功能所必需和充分的染色质重塑组分。这些结果与以前的研究结果表明，GR功能与多种形式的SWI/SNF复合物在体内。
We developed a model system to study glucocorticoid receptor (GR)-mediated chromatin remodeling by the BRG1 complex. Introduction of the BRG1 ATPase into the SW-13 cell line initiates the formation of a functional remodeling complex. This complex is able to induce transcriptional activation from a transiently transfected promoter with wild-type and chromatin-remodeling-deficient BRG1 mutants, suggesting that the complex possesses a coactivator function independent from remodeling. Transactivation from a chromatin template requires the BRG1 remodeling function, which induces regions of hypersensitivity and transcription factor loading onto the integrated MMTV promoter. We report that BRG1 remodeling activity is required for GR-mediated transactivation and that this activity cannot be replaced by other ATP-dependent remodeling proteins. Further characterization of the BRG1-associated factors (BAFs) present in these cells (for example, the expression of BAF250 but not BAF180) reveals that the BAF complex rather than the polybromo-associated BAF complex is the necessary and sufficient chromatin-remodeling component with which the receptor functions in vivo. These results in conjunction with previous findings demonstrate that the GR functions with multiple forms of the SWI/SNF complex in vivo.