Transcriptional regulation of the Bacillus subtilis bscR-CYP102A3 operon by the BscR repressor and differential induction of cytochrome CYP102A3 expression by oleic acid and palmitate.
The adjacent yrhI and yrhJ genes were identified by the Bacillus subtilis genome sequencing project. We now report that yrhJ (renamed CYP102A3) encodes a cytochrome P450 and that yrhI (renamed bscR) encodes a repressor that negatively regulates the transcription of the bscR-CYP102A3 operon. The transcriptional initiation site of bscR has been mapped by primer extension analysis. An 18-bp perfect palindromic sequence centered 65.5 bp downstream from the transcriptional initiation site of bscR has been identified as the binding site for BscR by gel mobility shift assays. Base substitutions in the 18-bp inverted repeat resulted in derepression of the bscR-xylE transcriptional fusion in vivo. bscR-xylE fusion studies and Northern blot analysis revealed that oleic acid and palmitate could induce the expression of the bscR-CYP102A3 operon to a considerable extent. However, only oleic acid was capable of preventing the binding of BscR to its operator DNA in vitro, suggesting that the induction of CYP102A3 expression by oleic acid and palmitate in B. subtilis might be mediated through different mechanisms.
Lee
T R
TR
Institute of Biochemistry, School of Life Science, National Yang-Ming University, Taipei, Taiwan.
Hsu
H P
HP
Shaw
G C
GC
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D001665:Binding Sites; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D004790:Enzyme Induction; D004794:Enzyme Repression; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D006899:Mixed Function Oxygenases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D009251:NADPH-Ferrihemoprotein Reductase; D019301:Oleic Acid / Q000494:pharmacology; D009876:Operon; D010168:Palmitates / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D012329:RNA, Bacterial / Q000096:biosynthesis; D012091:Repetitive Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D024363:Transcription Initiation Site; D015533:Transcriptional Activation
D001426:Bacterial Proteins; D010168:Palmitates; D012329:RNA, Bacterial; D012097:Repressor Proteins; C445020:bscR repressor protein, Bacillus subtilis; D019301:Oleic Acid; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C445019:CYP102A3 protein, Bacillus subtilis; D009251:NADPH-Ferrihemoprotein Reductase; C052423:flavocytochrome P450 BM3 monoxygenases