The sigE gene is required for normal expression of heterocyst-specific genes in Anabaena sp. strain PCC 7120.

ABSTRACT: The filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 produces specialized cells for nitrogen fixation called heterocysts. Previous work showed that the group 2 sigma factor sigE (alr4249; previously called sigF) is upregulated in differentiating heterocysts 16 h after nitrogen step-down. We now show that the sigE gene is required for normal heterocyst development and normal expression levels of several heterocyst-specific genes. Mobility shift assays showed that the transcription factor NtcA binds to sites in the upstream region of sigE and that this binding is enhanced by 2-oxoglutarate (2-OG). Deletions of the region containing the NtcA binding sites in P(sigE)-gfp reporter plasmids showed that the sites contribute to normal developmental regulation but are not essential

SUBMITTER: Mella-Herrera RA 

PROVIDER: S-EPMC3133031 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature