Removal of a ribosome small subunit-dependent GTPase confers salt resistance on Escherichia coli cells.
RsgA is a unique GTP hydrolytic protein in which GTPase activity is significantly enhanced by the small ribosomal subunit. Deletion of RsgA causes slow cell growth as well as defects in subunit assembly of the ribosome and 16S rRNA processing, suggesting its involvement in maturation of the small subunit. In this study, we found that removal of RsgA or inactivation of its ribosome small subunit-dependent GTPase activity provides Escherichia coli cells with resistance to high salt stress. Salt stress suppressed the defects in subunit assembly of the ribosome and processing of 16S rRNA as well as truncation of the 3' end of 16S rRNA in RsgA-deletion cells. In contrast, salt stress transiently impaired subunit assembly of the ribosome and processing of 16S rRNA and induced 3' truncation of 16S rRNA in wild-type cells. These results suggest that the action of RsgA on the ribosome, which usually facilitates maturation of the small subunit, disturbs it under a salt stress condition. Consistently, there was a drastic but transient decrease in the intracellular amount of RsgA after salt shock. Salt shock would make the pathway of maturation of the ribosome small subunit RsgA independent.
Hase
Yoichi
Y
Department of Biochemistry and Molecular Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki 036-8561, Japan.
Yokoyama
Shinichiro
S
Muto
Akira
A
Himeno
Hyouta
H
D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D020558:GTP Phosphohydrolases / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D017353:Gene Deletion; D009154:Mutation / Q000502:physiology; D054679:Ribosome Subunits, Small / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism; D055049:Salt Tolerance / Q000235:genetics*; D013312:Stress, Physiological / Q000502:physiology
D029968:Escherichia coli Proteins; D020558:GTP Phosphohydrolases; C467318:RsgA protein, E coli