Transcriptional activation by Bacillus subtilis ResD: tandem binding to target elements and phosphorylation-dependent and -independent transcriptional activation.
The expression of genes involved in nitrate respiration in Bacillus subtilis is regulated by the ResD-ResE two-component signal transduction system. The membrane-bound ResE sensor kinase perceives a redox-related signal(s) and phosphorylates the cognate response regulator ResD, which enables interaction of ResD with ResD-dependent promoters to activate transcription. Hydroxyl radical footprinting analysis revealed that ResD tandemly binds to the -41 to -83 region of hmp and the -46 to -92 region of nasD. In vitro runoff transcription experiments showed that ResD is necessary and sufficient to activate transcription of the ResDE regulon. Although phosphorylation of ResD by ResE kinase greatly stimulated transcription, unphosphorylated ResD, as well as ResD with a phosphorylation site (Asp57) mutation, was able to activate transcription at a low level. The D57A mutant was shown to retain the activity in vivo to induce transcription of the ResDE regulon in response to oxygen limitation, suggesting that ResD itself, in addition to its activation through phosphorylation-mediated conformation change, senses oxygen limitation via an unknown mechanism leading to anaerobic gene activation.
Geng
Hao
H
Department of Environmental and Biomolecular Systems, OGI School of Science & Engineering, Oregon Health & Science University, Beaverton, Oregon 97006, USA.
Nakano
Shunji
S
Nakano
Michiko M
MM
D001412:Bacillus subtilis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006420:Hemeproteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000235:genetics / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism*; D010100:Oxygen / Q000494:pharmacology; D010766:Phosphorylation; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D006420:Hemeproteins; D009566:Nitrates; C100386:ResD protein, Bacillus subtilis; D014157:Transcription Factors; C086193:flavohemoprotein, Bacteria; D009565:Nitrate Reductases; D050901:Nitrate Reductase; D010100:Oxygen