RNase E polypeptides lacking a carboxyl-terminal half suppress a mukB mutation in Escherichia coli.
We have isolated suppressor mutants that suppress temperature-sensitive colony formation and anucleate cell production of a mukB mutation. A linkage group (smbB) of the suppressor mutations is located in the rne/ams/hmp gene encoding the processing endoribonuclease RNase E. All of the rne (smbB) mutants code for truncated RNase E polypeptides lacking a carboxyl-terminal half. The amount of MukB protein was higher in these rne mutants than that in the rne+ strain. These rne mutants grew nearly normally in the mukB+ genetic background. The copy number of plasmid pBR322 in these rne mutants was lower than that in the rne+ isogenic strain. The results suggest that these rne mutations increase the half-lives of mukB mRNA and RNAI of pBR322, the antisense RNA regulating ColE1-type plasmid replication. We have demonstrated that the wild-type RNase E protein bound to polynucleotide phosphorylase (PNPase) but a truncated RNase E polypeptide lacking the C-terminal half did not. We conclude that the C-terminal half of RNase E is not essential for viability but plays an important role for binding with PNPase. RNase E and PNPase of the multiprotein complex presumably cooperate for effective processing and turnover of specific substrates, such as mRNAs and other RNAs in vivo.
Kido
M
M
Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, Kumamoto, Japan.
Yamanaka
K
K
Mitani
T
T
Niki
H
H
Ogura
T
T
Hiraga
S
S
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D002868:Chromosomal Proteins, Non-Histone; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D004722:Endoribonucleases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D018628:Gene Dosage; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D010957:Plasmids; D011117:Polyribonucleotide Nucleotidyltransferase / Q000378:metabolism; D013489:Suppression, Genetic; D013696:Temperature; D014161:Transduction, Genetic
D001426:Bacterial Proteins; D002868:Chromosomal Proteins, Non-Histone; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C067035:MukB protein, E coli; D010455:Peptides; D011117:Polyribonucleotide Nucleotidyltransferase; D004722:Endoribonucleases; C022537:ribonuclease E