Extensive overproduction of the AdhE protein by rng mutations depends on mutations in the cra gene or in the Cra-box of the adhE promoter.
Escherichia coli RNase G encoded by the rng gene is involved in degradation of adhE mRNA. Overproduction of the AdhE protein by rng mutants was found to depend on the genetic background of strains derived from DC272 (adhC81) or MC1061. We found that DC272 carried a point mutation in the Cra-binding site of the adhE promoter. The Cra protein encoded by the cra gene is known to act as a repressor of adhE. P1-phage-mediated transduction and lacZ fusion analysis with the mutant adhE promoter confirmed that this mutation is responsible for overproduction. On the other hand, Southern hybridization revealed that MC1061 had a 0.85-kb deletion of the cra gene. Overproduction of AdhE in the MC1061 background was reversed to the wild-type levels by introduction of a plasmid carrying the cra(+) gene. These results indicated that expression of the adhE gene was regulated transcriptionally by Cra and posttranscriptionally by RNase G.
Kaga
Naoko
N
Department of Bioengineering, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
Umitsuki
Genryou
G
Clark
David P
DP
Nagai
Kazuo
K
Wachi
Masaaki
M
D000426:Alcohol Dehydrogenase / Q000096:biosynthesis / Q000235:genetics*; D000445:Aldehyde Oxidoreductases / Q000096:biosynthesis / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D004722:Endoribonucleases / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000096:biosynthesis / Q000235:genetics*; D009154:Mutation; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D013045:Species Specificity; D056968:Lac Repressors
D000426:Alcohol Dehydrogenase; D000445:Aldehyde Oxidoreductases; D001426:Bacterial Proteins; D004722:Endoribonucleases; D029968:Escherichia coli Proteins; D009097:Multienzyme Complexes; D012097:Repressor Proteins; C489416:FruR protein, E coli; C068837:FruR protein, Bacteria; D056968:Lac Repressors; C068383:adhE protein, E coli; C081905:rng protein, E coli