The global regulators GacA and sigma(S) form part of a cascade that controls alginate production in Azotobacter vinelandii.

ABSTRACT: Transcription of the Azotobacter vinelandii algD gene, which encodes GDP-mannose dehydrogenase (the rate-limiting enzyme of alginate synthesis), starts from three sites: p1, p2, and p3. The sensor kinase GacS, a member of the two-component regulatory system, is required for transcription of algD from its three sites during the stationary phase. Here we show that algD is expressed constitutively throughout the growth cycle from the p2 and p3 sites and that transcription from p1 started at the transition between the exponential growth phase and stationary phase. We constructed A. vinelandii strains that carried mutations in gacA encoding the cognate response regulator of GacS and in rpoS coding for the stationary-phase sigma(S) factor. The gacA mutation impaired alginate production and trans

SUBMITTER: Castaneda M 

PROVIDER: S-EPMC95518 | biostudies-literature | 2001 Dec

REPOSITORIES: biostudies-literature