Regulation of Caulobacter crescentus ilvBN gene expression.
As part of an effort to determine the mechanisms employed by Caulobacter crescentus to regulate gene expression, the ilvBN genes encoding the two subunits of an acetohydroxy acid synthase (AHAS) have been characterized. Analysis of the DNA sequences indicated that the C. crescentus AHAS was highly homologous to AHAS isozymes from other organisms. S1 nuclease and primer extension studies demonstrated that transcription initiation occurred 172 bp upstream of the AHAS coding region. The region between the AHAS coding region and the transcription initiation site was shown to have the properties of a transcription attenuator. Deletion analysis of the region containing the stem-loop structure of the proposed attenuator resulted in the derepression of ilvBN expression. Thus, it appears that C. crescentus uses attenuation to regulate the expression of the ilvBN operon.
Tarleton
J C
JC
Department of Biological Sciences, University of South Carolina, Columbia 29208.
Malakooti
J
J
Ely
B
B
D000095:Acetolactate Synthase / Q000096:biosynthesis / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D016935:Caulobacter crescentus / Q000201:enzymology / Q000235:genetics*; D004252:DNA Mutational Analysis; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009876:Operon / Q000235:genetics; D014176:Protein Biosynthesis; D021382:Protein Sorting Signals / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D021382:Protein Sorting Signals; D012333:RNA, Messenger; D000095:Acetolactate Synthase