Regulation of the put operon in Salmonella typhimurium: characterization of promoter and operator mutations.
Regulation of the put operon in Salmonella typhimurium: characterization of promoter and operator mutations.
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鼠伤寒沙门氏菌中 put 操纵子的调节：启动子和操纵子突变的表征。
DOI：
10.1093/genetics/114.3.687
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发表时间：
1986
期刊：
影响因子：
3.3
通讯作者：
Maloy,SR
中科院分区：
文献类型：
--
作者：
Hahn,DR;Maloy,SR
这两个基因是ys利用脯氨酸所必需的。鼠伤寒形成一个发散的操纵子。脯氨酸可诱导putoperon的表达，并受分解代谢抑制。遗传证据表明，puta蛋白可以自抑制puta和putp基因的转录。为了建立putoperon调控的分子机制，我们分离了putcontrol区域的调控突变。这些突变体是通过两种表型选择的：(1)由于putaase活性的过度表达而能够降解有毒的脯氨酸类似物脱氢脯氨酸，或者(2)来自put::Mudoperon融合体的flacz过表达。每个突变在两个方向上对转录的影响是通过测量putta和putpoperon融合体中lacz的表达来确定的。当puta蛋白被注入内嵌体时，这些调控突变是显性的，它们位于两个基因之间的区域。突变体的表型表明：(1)putaa蛋白结合的putaa调控区有一个单一的操作位点，在两个方向上抑制转录；(2)putaa和putaa启动子重叠。
The two genes required for proline utilization byS. typhimuriumform a divergent operon. Expression of theputoperon is induced by proline and subject to catabolite repression. Genetic evidence suggests thatputAprotein autogenously represses transcription of theputAandputPgenes. In order to establish the molecular mechanism ofputoperon regulation we isolated regulatory mutations in theputcontrol region. These mutants were selected using two phenotypes: (1) the ability to degrade a toxic proline analogue, dehydroproline, due to overexpression ofputAenzyme activity, or (2) overexpression oflacZfromput::Mudoperon fusions. The effect of each mutation on transcription in both directions was determined by measuringlacZexpression fromputAandputPoperon fusions. These regulatory mutations werecis-dominant when theputAprotein was provided intrans, and they map in a region between the two genes. The phenotypes of the mutants suggest that (1) theputregulatory region has a single operator site where theputAprotein binds to repress transcription in both directions, and (2) theputAandputPpromoters overlap.