Transient recruitment of the hnRNP K protein to inducibly transcribed gene loci
Transient recruitment of the hnRNP K protein to inducibly transcribed gene loci
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DOI：
10.1093/nar/gkg452
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发表时间：
2003-07-15
影响因子：
14.9
通讯作者：
Bomsztyk, K
中科院分区：
文献类型：
--
作者：
Ostrowski, J;Kawata, Y;Bomsztyk, K
异质核核糖核蛋白K蛋白是一种RNA和DNA结合蛋白，参与调控包括基因表达在内的多种过程。我们使用染色质免疫沉淀（ChIP）试验，探讨K蛋白与血清诱导的，组成型表达和非转录基因位点在体内的相互作用。在大鼠HTC-IR肝癌细胞系中，血清处理诱导了两个即刻早期基因，hepatocellular-1和c-myc的mRNA水平的瞬时增加。ChIP分析表明，诱导的K-I和c-myc基因与K蛋白的瞬时招募到多个网站内的每个这些位点，包括启动子和转录区。相比之下，招募K蛋白的组成型转录β-肌动蛋白基因座和随机选择的非转录基因座要弱得多。在大鼠肾小球系膜细胞中，c-myc的组成型表达，而IL-1保持血清反应性。在这些细胞中，ChIP分析显示，血清诱导的招聘诱导型的c-myc基因座，但不是。用转录抑制剂放线菌素D预处理阻断了K蛋白与这些位点的诱导型结合，但不阻断K蛋白与这些位点的组成型结合。两者合计，本研究的结果表明，瞬时招募K蛋白的血清反应位点依赖于这些立即早期基因的诱导转录。
The heterogeneous nuclear ribonucleoprotein K protein is an RNA- and DNA-binding protein implicated in the regulation of multiple processes that comprise gene expression. We used chromatin immunoprecipitation (ChIP) assays to explore K protein interactions with serum-inducible, constitutively expressed and untranscribed gene loci in vivo. In the rat HTC-IR hepatoma cell line, serum treatment induced transient increases in the mRNA levels of two immediate-early genes, egr-1 and c-myc. ChIP analysis showed that the induction of egr-1 and c-myc genes was associated with a transient recruitment of K protein to multiple sites within each of these loci, including the promoter and transcribed regions. In contrast, recruitment of K protein to the constitutively transcribed beta-actin locus and to randomly chosen non-transcribed loci was far weaker. In rat mesangial cells, c-myc was constitutively expressed while egr-1 remained serum responsive. In these cells, ChIP analysis showed serum-induced recruitment to the inducible egr-1 but not to the c-myc locus. Pre-treatment with the transcription inhibitor actinomycin D blocked the inducible but not the constitutive binding of K protein to these loci. Taken together, the results of this study suggest that the transient recruitment of K protein to serum-responsive loci depends on the inducible transcription of these immediate-early genes.