The vacB gene required for virulence in Shigella flexneri and Escherichia coli encodes the exoribonuclease RNase R

被引:138
作者
Cheng, ZF [1 ]
Zuo, YH [1 ]
Li, ZW [1 ]
Rudd, KE [1 ]
Deutscher, MP [1 ]
机构
[1] Univ Miami, Sch Med, Dept Biochem & Mol Biol, Miami, FL 33101 USA
关键词
D O I
10.1074/jbc.273.23.14077
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
vacB, a gene previously shown to be required for expression of virulence in Shigella and enteroinvasive Escherichia coli, has been found to encode the 3'-5' exoribonuclease, RNase R. Thus, cloning off. coli vacB led to overexpression of RNase R activity, and partial deletion or interruption of the cloned gene abolished this overexpression, Interruption of the chromosomal copy of vacB eliminated endogenous RNase R activity; however, the absence of RNase R by itself had no effect on cell growth. In contrast, cells lacking both RNase R and polynucleotide phosphorylase were found to be inviable. These data indicate that RNase R participates in an essential cell function in addition to its role in virulence. The identification of the vacB gene product as RNase R should aid in understanding how the virulence phenotype in enterobacteria is expressed and regulated. On the basis of this information we propose that vacB be renamed rnr.
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页码:14077 / 14080
页数:4
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