In Rhizobium leguminosarum, NodD represses its own transcription by competing with RNA polymerase for binding sites.
We isolated RNA polymerase (RNAP) from Rhizobium leguminosarum, the nitrogen-fixing symbiont of peas and VICIA: Its 91 kDa subunit, which is homologous to sigma(70) of Escherichia coli RNAP, is necessary for transcription of the regulatory nodD gene, which in the presence of certain flavonoids induces transcription of other nod genes that are needed for the early steps of infection. We also show that negative autoregulation of nodD was achieved through competition between RNAP and NodD for their respective binding sites, which largely overlap. Combined with the result that high concentrations of the flavonoid inducer naringenin relieved the binding affinity of NodD for its target DNA, the way in which the nod genes are activated is discussed.
Hu
H
H
Shanghai Institute of Biochemistry, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China.
Liu
S
S
Yang
Y
Y
Chang
W
W
Hong
G
G
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D018983:DNA Footprinting; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D044950:Flavanones; D005419:Flavonoids / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000187:drug effects; D016961:Rhizobium leguminosarum / Q000235:genetics*; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D044950:Flavanones; D005419:Flavonoids; C060773:NodD protein, Bacteria; D012808:Sigma Factor; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; C005273:naringenin