Identification and characterization of hupT, a gene involved in negative regulation of hydrogen oxidation in Bradyrhizobium japonicum.
The Bradyrhizobium japonicum hupT gene was sequenced, and its gene product was found to be homologous to NtrB-like histidine kinases. A hupT mutant expresses higher levels of hydrogenase activity than the wild-type strain under hydrogenase-inducing conditions (i.e., microaerobiosis plus hydrogen, or symbiosis), whereas in noninduced hupT cells, hupSL expression is derepressed but does not lead to hydrogenase activity. We conclude that HupT is involved in the repression of HupSL synthesis at the transcriptional level but that enzymatic activation requires inducing conditions.
Van Soom
C
C
F. A. Janssens Laboratory of Genetics, Katholieke Universiteit Leuven, B-3001 Heverlee, Belgium.
Lerouge
I
I
Vanderleyden
J
J
Ruiz-Argüeso
T
T
Palacios
J M
JM
D000332:Aerobiosis; D020369:Bradyrhizobium / Q000235:genetics* / Q000378:metabolism*; D002874:Chromosome Mapping; D004252:DNA Mutational Analysis; D004789:Enzyme Activation / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D000071677:Histidine Kinase; D018398:Homeodomain Proteins / Q000235:genetics; D006859:Hydrogen / Q000378:metabolism*; D006864:Hydrogenase / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010084:Oxidation-Reduction; D010957:Plasmids; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics; D014158:Transcription, Genetic
D018398:Homeodomain Proteins; D015534:Trans-Activators; C088144:HoxA protein; D006859:Hydrogen; D006864:Hydrogenase; D011494:Protein Kinases; D000071677:Histidine Kinase