Back to Search
Start Over
The C-terminal half of RNase E, which organizes the Escherichia coli degradosome, participates in mRNA degradation but not rRNA processing in vivo.
- Source :
-
Molecular microbiology [Mol Microbiol] 1999 Jul; Vol. 33 (1), pp. 188-99. - Publication Year :
- 1999
-
Abstract
- RNase E is an essential Escherichia coli endonuclease, which controls both 5S rRNA maturation and bulk mRNA decay. While the C-terminal half of this 1061-residue protein associates with polynucleotide phosphorylase (PNPase) and several other enzymes into a 'degradosome', only the N-terminal half, which carries the catalytic activity, is required for growth. We characterize here a mutation (rne131 ) that yields a metabolically stable polypeptide lacking the last 477 residues of RNAse E. This mutation resembles the N-terminal conditional mutation rne1 in stabilizing mRNAs, both in bulk and individually, but differs from it in leaving rRNA processing and cell growth unaffected. Another mutation (rne105 ) removing the last 469 residues behaves similarly. Thus, the C-terminal half of RNase E is instrumental in degrading mRNAs, but dispensable for processing rRNA. A plausible interpretation is that the former activity requires that RNase E associates with other degradosome proteins; however, PNPase is not essential, as RNase E remains fully active towards mRNAs in rne+pnp mutants. All mRNAs are not stabilized equally by the rne131 mutation: the greater their susceptibility to RNase E, the larger the stabilization. Artificial mRNAs generated by E. coli expression systems based on T7 RNA polymerase can be genuinely unstable, and we show that the mutation can improve the yield of such systems without compromising cell growth.
- Subjects :
- Bacterial Proteins metabolism
DNA-Directed RNA Polymerases metabolism
Gene Expression Regulation, Bacterial
Macromolecular Substances
Peptide Fragments metabolism
RNA, Ribosomal, 5S metabolism
Recombinant Fusion Proteins metabolism
Viral Proteins
Bacterial Proteins chemistry
Endoribonucleases chemistry
Endoribonucleases metabolism
Escherichia coli enzymology
Multienzyme Complexes metabolism
Polyribonucleotide Nucleotidyltransferase metabolism
Protein Structure, Tertiary
RNA Helicases metabolism
RNA, Bacterial metabolism
RNA, Messenger metabolism
RNA, Ribosomal metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0950-382X
- Volume :
- 33
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Molecular microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 10411735
- Full Text :
- https://doi.org/10.1046/j.1365-2958.1999.01465.x