Escherichia coli histone-like protein H-NS preferentially binds to horizontally acquired DNA in association with RNA polymerase
Escherichia coli histone-like protein H-NS preferentially binds to horizontally acquired DNA in association with RNA polymerase
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DOI：
10.1093/dnares/dsl009
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发表时间：
2006-08-31
期刊：
影响因子：
4.1
通讯作者：
Ogasawara, Naotake
中科院分区：
文献类型：
--
作者：
Oshima, Taku;Ishikawa, Shu;Ogasawara, Naotake
热稳定核蛋白（Heat-stable nucleotid-structuring protein，H-NS）是大肠杆菌中表达的主要类核蛋白之一。除了在类核组织中的作用外，H-NS还作为基因表达的多效性调节剂发挥作用。利用高密度寡核苷酸芯片研究了H-NS的全基因组分布，并与RNA聚合酶和转录活性基因的分布进行了比较。本研究中使用的新方法显示，H-NS特异性结合约250个位点，覆盖>1000个基因，以维持转录失活。在>65%的具有低转录活性或无转录活性的H-NS结合位点中检测到RNA聚合酶，表明RNA聚合酶与启动子区域的缔合是H-NS转录抑制的一般模式。本研究还发现，大多数H-NS结合的DNA是水平获得的，这表明H-NS对不适当基因表达的抑制在E.大肠杆菌基因组。本研究对H-NS在大肠杆菌内的分布进行了全面的评估。大肠杆菌基因组，揭示了H-NS的转录调控机制，并提供了新的见解细菌基因组进化。
Heat-stable nucleoid-structuring protein (H-NS) is one of the main nucleoid proteins expressed in exponentially growing Escherichia coli cells. In addition to a role in nucleoid organization, H-NS functions as a pleiotropic regulator of gene expression. The genome-wide distribution of H-NS, compared with the distribution of RNA polymerase and transcriptionally active genes, was investigated using a high-density oligonucleotide chip. The new approach utilized in this study revealed that H-NS binds specifically to approximately 250 loci, covering >1000 genes, to maintain transcriptional inactivation. RNA polymerase was detected in >65% of H-NS binding sites with low or no transcriptional activity, indicating that the association of RNA polymerase to promoter regions is a general mode of transcription repression by H-NS. This study also revealed that most H-NS bound DNA have been horizontally acquired, which indicates that repression of inappropriate gene expression by H-NS plays an important role in the diversification of the E. coli genome. This study presents a comprehensive assessment of the distribution of H-NS within the E. coli genome, sheds light on the mechanism underlying the transcriptional regulation by H-NS, and provides new insight into bacterial genome evolution.