title: RNase Z in Escherichia coli plays a significant role in mRNA decay.
abstract: Genetic and biochemical analysis of RNase Z in eukaryotes, such as Arabadopsis thaliana, and prokaryotes like Bacillus subtilis have demonstrated that this endoribonuclease is essential for the maturation of tRNA precursors that do not contain a chromosomally encoded CCA determinant. As all Escherichia coli tRNA transcripts have chromosomally encoded CCA determinants, the function of its putative RNase Z homologue, the product of the elaC gene, is not clear. Here we demonstrate that the E. coli ElaC protein (RNase Z) endonucleolytically processes B. subtilis tRNA precursors lacking a CCA determinant both in vivo and in vitro. More importantly, E. coli RNase Z plays a significant role in mRNA decay, a previously unidentified activity for the enzyme. The purified RNase Z protein cleaves the rpsT mRNA at locations distinct from those obtained with RNase E. As expected, under physiological conditions E. coli and B. subtilis tRNA precursors containing a CCA determinant are not substrates. These results suggest a potentially important new role for the RNase Z family of proteins in RNA metabolism, particularly in organisms lacking RNase E.
authors.affiliation: Department of Genetics, University of Georgia, Athens, GA 30602, USA.
authors.forename: Tariq
authors.initials: T
authors.lastname: Perwez
authors.forename: Sidney R
authors.initials: SR
authors.lastname: Kushner
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D010727:Phosphoric Diester Hydrolases / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids; D020871:RNA Stability / Q000502:physiology*; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012343:RNA, Transfer; D004722:Endoribonucleases; C110250:RNase Z; C464943:ElaC protein, E coli; D010727:Phosphoric Diester Hydrolases; C022537:ribonuclease E