The endoribonucleolytic N-terminal half of Escherichia coli RNase E is evolutionarily conserved in Synechocystis sp. and other bacteria but not the C-terminal half, which is sufficient for degradosome assembly.
Escherichia coli RNase E, an essential single-stranded specific endoribonuclease, is required for both ribosomal RNA processing and the rapid degradation of mRNA. The availability of the complete sequences of a number of bacterial genomes prompted us to assess the evolutionarily conservation of bacterial RNase E. We show here that the sequence of the N-terminal endoribonucleolytic domain of RNase E is evolutionarily conserved in Synechocystis sp. and other bacteria. Furthermore, we demonstrate that the Synechocystis sp. homologue binds RNase E substrates and cleaves them at the same position as the E. coli enzyme. Taken together these results suggest that RNase E-mediated mechanisms of RNA decay are not confined to E. coli and its close relatives. We also show that the C-terminal half of E. coli RNase E is both sufficient and necessary for its physical interaction with the 3'-5' exoribonuclease polynucleotide phosphorylase, the RhlB helicase, and the glycolytic enzyme enolase, which are components of a "degradosome" complex. Interestingly, however, the sequence of the C-terminal half of E. coli RNase E is not highly conserved evolutionarily, suggesting diversity of RNase E interactions with other RNA decay components in different organisms. This notion is supported by our finding that the Synechocystis sp. RNase E homologue does not function as a platform for assembly of E. coli degradosome components.
Kaberdin
V R
VR
Institute of Microbiology and Genetics, Vienna Biocenter, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria.
Miczak
A
A
Jakobsen
J S
JS
Lin-Chao
S
S
McDowall
K J
KJ
von Gabain
A
A
D001483:Base Sequence; D017124:Conserved Sequence; D000458:Cyanobacteria / Q000201:enzymology* / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D004722:Endoribonucleases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D019143:Evolution, Molecular; D046911:Macromolecular Substances; D012323:RNA Processing, Post-Transcriptional; D012329:RNA, Bacterial / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism; D013045:Species Specificity; D013379:Substrate Specificity
D017931:DNA Primers; D046911:Macromolecular Substances; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D004722:Endoribonucleases; C022537:ribonuclease E