Transcription factor YB-1 mediates DNA polymerase α gene expression
Transcription factor YB-1 mediates DNA polymerase α gene expression
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DOI：
10.1074/jbc.m413353200
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发表时间：
2005-03-04
影响因子：
4.8
通讯作者：
Mertens, PR
中科院分区：
文献类型：
--
作者：
En-Nia, A;Yilmaz, E;Mertens, PR
Y盒蛋白-1参与细胞周期蛋白A和B1基因调控最近已被证明。一个更普遍的作用，这种蛋白质的细胞复制被假设为众多的细胞周期相关基因的调控序列含有推定的结合位点。在本研究中，DNA聚合酶α（DPA）基因被鉴定为另一个YB-1应答基因，其在血清应答启动子区具有Y盒和3'反向重复序列，命名为DPA RE-1。过表达的YB-1浓度依赖性反式激活DPA基因的表达，在报告分析和西南印迹以及DNA结合分析显示不同的内源性蛋白质的结合与RE-1的分子大小为26，32和52 kDa。其中，YB-1结合确认使用重组以及内源性蛋白质，优先单链DNA结合。系膜细胞早期血清生长反应伴随着核YB-1移位和RE-1处的核复合物形成。DPA RE-1序列的精细作图揭示了在异源SV 40启动子的背景下，反式调节与基因激活对辅因子的依赖性，但在缩短的同源启动子序列的背景下，抑制。一个YB-1敲低导致DPA转录率下降，并取消DPA转录的血清依赖性诱导。这些结果将YB-1与DPA基因表达的血清反应性联系起来，并提供了对所需序列和蛋白结合背景的了解。
Y-box protein-1 involvement in cyclin A and B1 gene regulation has recently been demonstrated. A more generalized role of this protein for cell replication is hypothesized as numerous regulatory sequences of cell cycle-related genes contain putative binding sites. In the present study the DNA polymerase alpha (DPA) gene is identified as another YB-1-responsive gene with a Y-box and 3' inverted repeat sequence, designated DPA RE-1, in the serum-responsive promoter region. Overexpressed YB-1 concentration-dependently trans-activated DPA gene expression in reporter assays and Southwestern blotting as well as DNA binding analyses revealed binding of distinct endogenous proteins to the RE-1 with molecular sizes of 26, 32 and 52 kDa. Among these, YB-1 binding was confirmed using recombinant as well as endogenous proteins, with preferential single-stranded DNA binding. Early serum growth response in mesangial cells was accompanied by a nuclear YB-1 shift and nucleocomplex formation at the RE-1. Fine mapping of the DPA RE-1 sequence unraveled a dependence on co-factors for trans-regulation with gene activation in the context of a heterologous SV40 promoter but suppression in the context of the abbreviated homologous promoter sequence. A YB-1 knock down resulted in decreased DPA transcription rates and abrogated the serum-dependent induction of DPA transcription. These results link YB-1 with serum responsiveness of DPA gene expression and provide insight into the required sequence and protein binding context.