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首页> 外文期刊>Journal of bacteriology >H-NS Is a Repressor of the Proteus mirabilis Urease Transcriptional Activator GeneureR
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H-NS Is a Repressor of the Proteus mirabilis Urease Transcriptional Activator GeneureR

机译：H-NS是奇异变形杆菌脲酶转录激活因子GeneureR的阻遏物

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Expression of Proteus mirabilis urease is governed by UreR, an AraC-like positive transcriptional activator. A poly(A) tract nucleotide sequence, consisting of A6TA2CA2TGGTA5GA6TGA5, is located 16 bp upstream of the ?70-likeureR promoter P2. Since poly(A) tracts of DNA serve as binding sites for the gene repressor histone-like nucleoid structuring protein (H-NS), we measured β-galactosidase activity of wild-typeEscherichia coli MC4100 (H-NS+) and its isogenic derivative ATM121 (hns::Tn10) (H-NS?) harboring a ureR-lacZ operon fusion plasmid (pLC9801). β-Galactosidase activity in the H-NS? host strain was constitutive and sevenfold greater (P < 0.0001) than that in the H-NS+ host. A recombinant plasmid containing cloned P. mirabilis hns was able to complement and restore repression of the ureR promoter in the H-NS?host when provided in trans. Deletion of the poly(A) tract nucleotide sequence from pLC9801 resulted in an increase in β-galactosidase activity in the H-NS+ host to nearly the same levels as that observed for wild-type pLC9801 harbored by the H-NS?host. Urease activity in strains harboring the recombinant plasmid pMID1010 (encoding the entire urease gene cluster of P. mirabilis) was equivalent in both the H-NS?background and the H-NS+ background in the presence of urea but was eightfold greater (P = 0.0001) in the H-NS? background in the absence of urea. We conclude that H-NS represses ureR expression in the absence of urea induction.
机译：奇异变形杆菌脲酶的表达受UreR（一种AraC样阳性转录激活因子）控制。多核苷酸（A）核苷酸序列，由A 6 TA 2 CA 2 TGGTA 5 GA 6 TGA 5 ，位于？ 70 -like ureR 启动子P2上游16 bp。由于DNA的多聚（A）片段是基因阻遏物组蛋白样核苷酸样结构蛋白（H-NS）的结合位点，因此我们测量了野生型大肠杆菌 MC4100（H -NS + ）及其等价衍生物ATM121（ hns :: Tn 10 ）（H-NS ？）带有 ureR-lacZ 操纵子融合质粒（pLC9801）。 H-NS ？宿主菌株中的β-半乳糖苷酶活性是组成性的，是H-NS + P <0.0001） >主机。含有克隆的 P的重组质粒。反式提供时，mirabilis hns 能够补充并恢复H-NS ？宿主中 ureR 启动子的阻遏。从pLC9801中删除多聚核苷酸序列导致H-NS + 宿主中的β-半乳糖苷酶活性增加到与野生型pLC9801所观察到的水平几乎相同的水平。 H-NS ？主机。在H-NS ？背景和H-NS中，带有重组质粒pMID1010（编码 P。mirabilis 的整个脲酶基因簇）的菌株中的脲酶活性均相同。在有尿素的情况下， + 背景，但在不存在尿素的情况下，H-NS ？背景下的背景 + 大八倍（ P = 0.0001）。我们得出的结论是，在没有尿素诱导的情况下，H-NS抑制 ureR 表达。

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