Transcriptional activation of a heat-shock gene, lonD, of Myxococcus xanthus by a two component histidine-aspartate phosphorelay system.
In vitro transcription of lonD, a heat-shock gene from Myxococcus xanthus, was stimulated in the presence of extract from heat-shocked cells. For this stimulation the upstream promoter region of lonD was found to be essential. Activation of lonD transcription was also observed when extract from non-heat-shocked cells was heat treated in vitro at 42 degrees C for 10 min. A DNA binding assay and footprinting analysis revealed that a factor(s) binds to the upstream region from -122 to -107 with respect to the transcription initiation site. This region was required for heat-shock induction of lonD expression both in vitro and in vivo. The lonD promoter-binding protein named HsfA was purified, and its gene was cloned. Analysis of the DNA sequence reveals that HsfA is a response regulator of the two-component system and shows high sequence similarity to the NtrC family or the enhancer-binding proteins. Upstream of hsfA, a gene encoding a histidine kinase was identified and named hsfB. HsfB was found to be autophosphorylated and able to phosphorylate HsfA. HsfA with HsfB activated in vitro transcription of lonD in a manner dependent on RNA polymerase containing SigA, the housekeeping sigma factor of M. xanthus.
Ueki
Toshiyuki
T
Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
Inouye
Sumiko
S
D001483:Base Sequence; D001665:Binding Sites; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000235:genetics*; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics; D000071677:Histidine Kinase; D008969:Molecular Sequence Data; D016941:Myxococcus xanthus / Q000235:genetics*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000235:genetics*; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; D011994:Recombinant Proteins; D011494:Protein Kinases; D000071677:Histidine Kinase