A GENETIC-ANALYSIS OF F SEX FACTOR CISTRONS NEEDED FOR SURFACE EXCLUSION IN ESCHERICHIA-COLI
A GENETIC-ANALYSIS OF F SEX FACTOR CISTRONS NEEDED FOR SURFACE EXCLUSION IN ESCHERICHIA-COLI
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DOI：
10.1016/0022-2836(80)90065-0
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发表时间：
1980-01-01
影响因子：
5.6
通讯作者：
WILLETTS, N
中科院分区：
文献类型：
--
作者：
ACHTMAN, M;MANNING, PA;WILLETTS, N
将编码表面排斥的F质粒的结构基因预先克隆到载体质粒pSC 101中以产生嵌合质粒pRS 31。通过体外诱变在pRS31中产生部分地破坏表面排斥的点突变。这些突变用于证明2个独立的顺反子traS和traT，每个顺反子仅编码表面排斥现象的2个方面中的1个。当这些突变被遗传转移到Flac时，它们影响表面排斥，但不影响F皮利的合成或在缀合中充当供体的能力。分离出60个Flac突变体，它们在产生表面排斥方面完全或仅部分缺陷。这些突变体，只有部分缺陷携带traS或traT突变。大多数其他突变是在traJ顺反子，这是参与转录调控的反操纵子。后者的突变体在纤毛形成和DNA转移方面都有缺陷。还有一些突变体携带表面排斥顺反子极性突变或携带多个突变。这些结果表明F质粒含有2个用于表面排斥的结构顺反子和1个参与转录调控的顺反子。
The structural genes of the F plasmid which encode surface exclusion were previously cloned in the vector plasmid pSC101 to yield the chimeric plasmid pRS31. Point mutations which partially inactivate surface exclusion were generated in pRS31 by in vitro mutagenesis. These mutations were used to demonstrate that 2 independent cistrons, traS and traT, each encodes only 1 of the 2 aspects of the surface exclusion phenomenon. When these mutations were moved genetically to Flac, they affected surface exclusion but did not affect either the synthesis of F pili or the ability to act as a donor in conjugation. Sixty mutants of Flac were isolated which were either totally or only partially defective in producing surface exclusion. Those mutants which were only partially defective carried either traS or traT mutations. Most of the other mutations were in the traJ cistron, which is involved in transcriptional regulation of the tra operon. These latter mutants were defective in F piliation and also in DNA transfer. Still other mutants carried mutations which were polar on the surface exclusion cistrons or carried multiple mutations. These results demonstrate that the F plasmid contains 2 structural cistrons for surface exclusion and 1 cistron which is involved in transcriptional regulation.