RNase E is required for induction of the glutamate-dependent acid resistance system in Escherichia coli.
The Escherichia coli RNase E is an essential endoribonuclease involved in processing and/or degradation of rRNAs, tRNAs, and non-coding small RNAs as well as many mRNAs. It is known that RNase E activity is somehow regulated by an RNA-binding protein Hfq, at least in some cases. We searched for proteins that showed changes in expression in both hfq::cat and rne-1 mutant cells as compared with the wild type, and found that a protein band of 49-kDa decreased in these mutant cells at 42 degrees C, the restrictive temperature for rne-1. N-terminal amino acid sequencing identified it as a mixture of GadA and GadB, two isozymes of glutamate decarboxylase involved in glutamate-dependent acid resistance. The rne-1 mutant as well as the hfq mutant showed decreased survival under acidic conditions (pH 2.5). Hfq is known to regulate the expression of GadA/B in RpoS- and GadY small RNA-dependent ways. We examined the expression of these two regulators in rne-1 mutant cells. In the mutant cells, the induction of GadY was defective at 42 degrees C, but the expression of RpoS was normal. These results indicate that RNase E is required for induction of the glutamate-dependent acid resistance system in a RpoS-independent manner.
Takada
Ayako
A
Department of Bioengineering, Tokyo Institute of Technology, Japan.
Umitsuki
Genryou
G
Nagai
Kazuo
K
Wachi
Masaaki
M
D001426:Bacterial Proteins / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D004722:Endoribonucleases / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D018698:Glutamic Acid / Q000494:pharmacology*; D035001:Host Factor 1 Protein / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D012808:Sigma Factor / Q000378:metabolism
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C087373:Hfq protein, E coli; D035001:Host Factor 1 Protein; D008565:Membrane Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D018698:Glutamic Acid; D004722:Endoribonucleases; C022537:ribonuclease E