Ribonuclease E modulation of the bacterial SOS response.
Plants, animals, bacteria, and Archaea all have evolved mechanisms to cope with environmental or cellular stress. Bacterial cells respond to the stress of DNA damage by activation of the SOS response, the canonical RecA/LexA-dependent signal transduction pathway that transcriptionally derepresses a multiplicity of genes-leading to transient arrest of cell division and initiation of DNA repair. Here we report the previously unsuspected role of E. coli endoribonuclease RNase E in regulation of the SOS response. We show that RNase E deletion or inactivation of temperature-sensitive RNase E protein precludes normal initiation of SOS. The ability of RNase E to regulate SOS is dynamic, as down regulation of RNase E following DNA damage by mitomycin C resulted in SOS termination and restoration of RNase E function leads to resumption of a previously aborted response. Overexpression of the RraA protein, which binds to the C-terminal region of RNase E and modulates the actions of degradosomes, recapitulated the effects of RNase E deficiency. Possible mechanisms for RNase E effects on SOS are discussed.
Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America.
Robert
R
Manasherob
Christine
C
Miller
Kwang-sun
KS
Kim
Stanley N
SN
Cohen
D001419:Bacteria / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D004249:DNA Damage; D004269:DNA, Bacterial; D004722:Endoribonucleases / Q000378:metabolism*; D005434:Flow Cytometry; D013014:SOS Response, Genetics
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004722:Endoribonucleases; C022537:ribonuclease E