PRODUCTS OF NITROGEN REGULATORY GENES NTRA AND NTRC OF ENTERIC BACTERIA ACTIVATE GLNA TRANSCRIPTION INVITRO - EVIDENCE THAT THE NTRA PRODUCT IS A SIGMA-FACTOR
PRODUCTS OF NITROGEN REGULATORY GENES NTRA AND NTRC OF ENTERIC BACTERIA ACTIVATE GLNA TRANSCRIPTION INVITRO - EVIDENCE THAT THE NTRA PRODUCT IS A SIGMA-FACTOR
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DOI：
10.1073/pnas.82.22.7525
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发表时间：
1985-01-01
影响因子：
11.1
通讯作者：
KUSTU, S
中科院分区：
文献类型：
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作者：
HIRSCHMAN, J;WONG, PK;KUSTU, S
在肠道细菌[沙门氏菌属、埃希氏菌属、克雷伯氏菌属]中，两种氮调节基因ntrA和ntrC的产物在体内和体外均激活glnA（编码谷氨酰胺合成酶的结构基因）的转录。ntrC产物（gpntrC）是一种DNA结合蛋白，它与glnA启动子调控区的5个位点结合，似乎可以激活转录起始。作为一种分析的刺激glnA转录在体外转录-翻译系统中的耦合，我们已经部分纯化的ntrA基因产物（gpntrA）。以下证据与gpntrA是σ的观点一致。RNA聚合酶亚基：（i）gpntrA活性通过几个步骤与RNA聚合酶的σ 70全酶（E σ 70）和核心（E）形式共纯化，但可以通过肝素琼脂糖上的色谱法与它们分离。(ii)通过分子筛层析进一步纯化后，部分纯化的gpntrA级分允许glnA从体内使用的相同起始点转录;转录依赖于gpntrC和添加的E。gpntrA级分不允许从我们用作对照的启动子（包括lacUV 5）转录。E σ 70具有反向特异性。
In enteric bacteria [Salmonella, Escherichia, Klebsiella] the products of two nitrogen regulatory genes, ntrA and ntrC, activate transcription of glnA, the structural gene encoding glutamine synthetase, both in vivo and in vitro. The ntrC product (gpntrC) is a DNA-binding protein, which binds to five sites in the glnA promoter-regulatory region and appears to activate transcription initiation. Using as an assay the stimulation of glnA transcription in a coupled in vitro transcription-translation system, we have partially purified the ntrA gene product (gpntrA). The following evidence is consistent with the view that gpntrA is a .sigma. subunit for RNA polymerase: (i) The gpntrA activity copurifies with the .sigma.70 holoenzyme (E.sigma.70) and core (E) forms of RNA polymerase through several steps but can be separated from them by chromatography on heparin agarose. (ii) After further purification by molecular sieve chromatography, the partially purified gpntrA fraction allows transcription of glnA from the same startpoint used in vivo; transcription is dependent on gpntrC and on added E. The gpntrA fraction does not allow transcription from promoters that we have used as controls, including lacUV5 .cntdot. E.sigma.70 has the reverse specificity.