Nitrogen regulation of the codBA (cytosine deaminase) operon from Escherichia coli by the nitrogen assimilation control protein, NAC.

ABSTRACT: Transcription of the cytosine deaminase (codBA) operon of Escherichia coli is regulated by nitrogen, with about three times more codBA expression in cells grown in nitrogen-limiting medium than in nitrogen-excess medium. Beta-galactosidase expression from codBp-lacZ operon fusions showed that the nitrogen assimilation control protein NAC was necessary for this regulation. In vitro transcription from the codBA promoter with purified RNA polymerase was stimulated by the addition of purified NAC, confirming that no other factors are required. Gel mobility shifts and DNase I footprints showed that NAC binds to a site centered at position -59 relative to the start site of transcription and that mutants that cannot bind NAC there cannot activate transcription. When a longer promoter region (posi

SUBMITTER: Muse WB 

PROVIDER: S-EPMC154391 | biostudies-literature | 2003 May

REPOSITORIES: biostudies-literature