HoxA is a transcriptional regulator for expression of the hup structural genes in free-living Bradyrhizobium japonicum.

Abstract

A chromosomally integrated Bradyrhizobium japonicum hoxA mutant is unable to oxidize hydrogen in free-living conditions. Derepressing conditions that induce hydrogenase activity in free-living, wild-type B. japonicum cells cannot induce expression of the hydrogenase structural genes in the hoxA mutant. The DNA-binding capacity of HoxA at the hup promoter region was studied by means of gel retardation. Both heterotrophically growing cells and cells induced to express hydrogenase activity contain a protein that specifically binds to the hup promoter region. Crude protein extracts isolated from a B. japonicum hoxA mutant do not contain this binding compound. The HoxA protein was overexpressed in E. coli and isolated in the form of a maltose-binding protein (MBP)-HoxA fusion. The MBP-HoxA hybrid protein specifically bound to a 50 bp region of the hupSL promoter known to be important for regulation of hupSL expression.

Cite this paper

@article{Soom1997HoxAIA, title={HoxA is a transcriptional regulator for expression of the hup structural genes in free-living Bradyrhizobium japonicum.}, author={Carolien van Soom and Peter Christianus Martinus de Wilde and Jos Vanderleyden}, journal={Molecular microbiology}, year={1997}, volume={23 5}, pages={967-77} }