当前位置： SCI文献检索 > JOURNAL OF BACTERIOLOGY期刊下所有文献 > The Bradyrhizobium japonicum rpoH1 gene encoding a sigma 32-like protein is part of a unique heat shock gene cluster together with groESL1 and three small heat shock genes.

The Bradyrhizobium japonicum rpoH1 gene encoding a sigma 32-like protein is part of a unique heat shock gene cluster together with groESL1 and three small heat shock genes.

Abstract：

:The heat shock response of Bradyrhizobium japonicum is controlled by a complex network involving two known regulatory systems. While some heat shock genes are controlled by a highly conserved inverted-repeat structure (CIRCE), others depend on a sigma 32-type heat shock sigma factor. Using Western blot (immunoblot) analysis, we confirmed the presence of a sigma 32-like protein in B. japonicum and defined its induction pattern after heat shock. A B. japonicum rpoH-like gene (rpoH1) was cloned by complementation of an Escherichia coli strain lacking sigma 32. A knockout mutation in rpoH1 did not abolish sigma 32 production in B. japonicum, and the rpoH1 mutant showed the wild-type growth phenotype, suggesting the presence of multiple rpoH homologs in this bacterium. Further characterization of the rpoH1 gene region revealed that the rpoH1 gene is located in a heat shock gene cluster together with the previously characterized groESL1 operon and three genes encoding small heat shock proteins in the following arrangement: groES1, groEL1, hspA, rpoH1, hspB, and hspC. Three heat-inducible promoters are responsible for transcription of the six genes as three bicistronic operons. A sigma 32-dependent promoter has previously been described upstream of the groESL1 operon. Although the hspA-rpoH1 and hspBC operons were clearly heat inducible, they were preceded by sigma 70-like promoters. Interestingly, a stretch of about 100 bp between the transcription start site and the start codon of the first gene in each of these two operons was nearly identical, making it a candidate for a regulatory element potentially allowing heat shock induction of sigma 70-dependent promoters.

journal_name

J Bacteriol

journal_title

Journal of bacteriology

authors

Narberhaus F,Weiglhofer W,Fischer HM,Hennecke H

doi

10.1128/jb.178.18.5337-5346.1996

subject

Has Abstract

pub_date

1996-09-01 00:00:00

pages

5337-46

issue

eissn

0021-9193

issn

1098-5530

journal_volume

178

pub_type

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The Bradyrhizobium japonicum rpoH1 gene encoding a sigma 32-like protein is part of a unique heat shock gene cluster together with groESL1 and three small heat shock genes.