Exportin 4 interacts with Sox9 through the HMG Box and inhibits the DNA binding of Sox9.
Exportin 4 interacts with Sox9 through the HMG Box and inhibits the DNA binding of Sox9.
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DOI：
10.1371/journal.pone.0025694
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发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
Hiraoka Y
中科院分区：
文献类型：
--
作者：
Tsuchiya M;Ogawa H;Suzuki T;Sugiyama N;Haraguchi T;Hiraoka Y
SOX9是哺乳动物组织发育所必需的转录因子。一般说来，这类转录因子需要共调控因子来精确地在时间和空间上控制胚胎发育过程中许多精确发育所必需的基因的激活和失活。在这里，我们鉴定了一种新的Sox9协同调节蛋白：利用固定化Sox9蛋白的亲和层析，我们鉴定Exportin 4(Exp4)是人培养细胞中与Sox9相互作用的蛋白。用抗Sox9抗体进行免疫沉淀实验，证实了内源性Exp4和Sox9蛋白在人骨肉瘤U2OS细胞中的相互作用。去除Exp4的siRNA可促进Sox9靶基因在U2OS细胞中的转录，但不影响Sox9的核定位。这些结果表明，Exp4调节细胞核中的Sox9活性。此外，我们发现Sox9的HMG盒负责与Exp4结合，而HMG盒是抑制Sox9介导的转录所必需的。这与已知的与其转录激活结构域结合的Sox9共调控因子形成了鲜明对比。染色质免疫沉淀分析表明，Exp4阻止Sox9与其靶基因的增强子结合。这些结果表明，Exp4作为Sox9的辅助调节因子，直接调节Sox9与其靶基因的结合。
Sox9 is a transcription factor that is required for tissue development in mammals. In general, such transcription factors require co-regulators for precise temporal and spatial control of the activation and inactivation of the numerous genes necessary for precise development during embryogenesis. Here we identify a new Sox9 co-regulator: Using affinity chromatography with immobilized Sox9 protein, we identified exportin 4 (Exp4) as an interacting protein of Sox9 in human cultured cells. Interaction between endogenous Exp4 and Sox9 proteins was confirmed in the human osteosarcoma U2OS cells by immunoprecipitation experiments using anti-Sox9 antibody. siRNA depletion of Exp4 enhanced transcription of Sox9 target genes in U2OS cells, but did not affect nuclear localization of Sox9. These results suggest that Exp4 regulates Sox9 activity in the nucleus. Furthermore we found that the HMG box of Sox9 was responsible for binding to Exp4, and the HMG box was required for suppression of Sox9-mediated transcription. This contrasts with the known Sox9 co-regulators which bind to its transcriptional activation domain. Chromatin immunoprecipitation analyses revealed that Exp4 prevents Sox9 binding to the enhancers of its target genes. These results demonstrate that Exp4 acts as a Sox9 co-regulator that directly regulates binding of Sox9 to its target genes.
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影响因子：
3.5
作者：
Chan, CK;Jans, DA
通讯作者：
Jans, DA
DOI：
10.1073/pnas.0407510102
发表时间：
2005-02-15
影响因子：
11.1
作者：
Kawakami, Y;Tsuda, M;Asahara, H
通讯作者：
Asahara, H
影响因子：
5.3
作者：
Lefebvre, V;Huang, WD;deCrombrugghe, B
通讯作者：
deCrombrugghe, B
影响因子：
4.8
作者：
Hattori, Takako;Eberspaecher, Heidi;de Crombrugghe, Benoit
通讯作者：
de Crombrugghe, Benoit
影响因子：
2.9
作者：
Obsil, T;Ghirlando, R;Dyda, F
通讯作者：
Dyda, F