Identification of a Locus Upstream from the Hydrogenase Structural Genes That Is Involved in Hydrogenase Expression in Bradyrhizobium japonicum†

AUTOR(ES)

Novak, Patricia D.

RESUMO

A locus involved in the expression of the uptake hydrogenase system of Bradyrhizobium japonicum was identified adjacent to genes encoding the hydrogenase subunits. A cloned fragment of DNA was used to complement to autotrophy a Hup− putative regulatory mutant of B. japonicum. The mutant strain lacked hydrogenase activity and synthesized low levels of the large subunit of hydrogenase as determined by Western gels. Tn5-induced mutagenesis located the region within the fragment which was necessary for complementation of the mutant phenotype. The locus identified is adjacent to that encoding the small subunit of hydrogenase; its right border is <0.5 kilobase upstream from the hydrogenase transcriptional start site, and its left border is between 1 and 2.5 kilobases from that start site. However, the locus is outside the region previously shown to contain hup-related genes of B. japonicum. Thus, the localization of this gene describes a previously unidentified hup-related gene on a region of DNA not previously shown to contain hup-specific DNA.

Documentos Relacionados

• A genetic region downstream of the hydrogenase structural genes of Bradyrhizobium japonicum that is required for hydrogenase processing.
• Identification of a locus within the hydrogenase gene cluster involved in intracellular nickel metabolism in Bradyrhizobium japonicum.
• Cloning and expression of Bradyrhizobium japonicum uptake hydrogenase structural genes in Escherichia coli
• Cloning and expression of Bradyrhizobium japonicum uptake hydrogenase structural genes in Escherichia coli.
• The FixK2 Protein Is Involved in Regulation of Symbiotic Hydrogenase Expression in Bradyrhizobium japonicum