Metastable regulation of type 1 piliation in Escherichia coli and isolation and characterization of a phenotypically stable mutant.
Metastable regulation of type 1 piliation in Escherichia coli and isolation and characterization of a phenotypically stable mutant.
复制标题
大肠杆菌中 1 型纤毛作用的亚稳态调节以及表型稳定突变体的分离和表征。
DOI：
10.1128/jb.168.1.179-185.1986
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发表时间：
1986
影响因子：
3.2
通讯作者：
Orndorff,PE
中科院分区：
文献类型：
--
作者：
Spears,PA;Schauer,D;Orndorff,PE
大肠杆菌的1型菌毛化由于一个小的，约1000个纤毛的倒位而表现出相变化。300个碱基对，调节pilA（fimA）的元件，该基因编码皮利的结构亚基（Abraham等人，Proc. Natl. Acad. Sci. USA 82：5724-5727，1985）。我们已经使用倒位作为一种测定来表征稳定的有毛突变体。突变株没有表现出野生型特征的pilA ON和pilA OFF菌落变体;相反，每个克隆产生的pilA表达水平介于ON和OFF野生型群体之间。该突变表型是由hemA和trpA之间的一个以前未描述的位点处的病变所赋予的，我们将其称为pilG。在四个pilG突变群体中pilA启动子区域的检查表明，pilG突变所赋予的表型稳定性不是由于不能进行倒位。相反，所有pilG突变群体由ON和OFF个体的大致相等的混合物组成。我们认为，pilG突变体可能会经历这样的快速开关的pilA启动子，人口表现出中等水平的pilA表达和表型稳定性。
Type 1 piliation in Escherichia coli exhibits phase variation due to the inversion of a small, ca. 300-base-pair, element that regulates pilA (fimA), the gene that encodes the structural subunit of pili (Abraham et al., Proc. Natl. Acad. Sci. USA 82:5724-5727, 1985). We have used the inversion as an assay to characterize a stably piliated mutant. The mutant strain did not exhibit the pilA ON and pilA OFF colonial variants characteristic of the wild type; rather, every clone produced a level of pilA expression intermediate between ON and OFF wild-type populations. The mutant phenotype was conferred by a lesion at a previously undescribed locus between hemA and trpA, which we have termed pilG. Examination of the pilA promoter region in four pilG mutant populations indicated that the phenotypic stability conferred by the pilG mutation was not due to an inability to carry out the inversion. Rather, all pilG mutant populations consisted of approximately equal mixtures of ON and OFF individuals. We suggest that pilG mutants may undergo such rapid switching of the pilA promoter that populations exhibit an intermediate level of pilA expression and phenotypic stability.