Nitrate/nitrite assimilation system of the marine picoplanktonic cyanobacterium Synechococcus sp. strain WH 8103: effect of nitrogen source and availability on gene expression.

ABSTRACT: The genes encoding the structural components of the nitrate/nitrite assimilation system of the oceanic cyanobacterium Synechococcus sp. strain WH 8103 were cloned and characterized. The genes encoding nitrate reductase (narB) and nitrite reductase (nirA) are clustered on the chromosome but are organized in separate transcriptional units. Upstream of narB is a homologue of nrtP that encodes a nitrate/nitrite-bispecific permease rather than the components of an ABC-type nitrate transporter found in freshwater cyanobacteria. Unusually, neither nirA nor ntcA (encoding a positive transcription factor of genes subject to nitrogen control) were found to be tightly regulated by ammonium. Furthermore, transcription of glnA (encoding glutamine synthetase) is up-regulated in ammonium-grown cells, hig

SUBMITTER: Bird C 

PROVIDER: S-EPMC310010 | biostudies-literature | 2003 Dec

REPOSITORIES: biostudies-literature