Control of Bacillus subtilis glutamine synthetase expression by glnR from Staphylococcus aureus.

GlnR plays a major role in regulation in Bacillus subtilis by directly controlling expression of glutamine synthetase (GS) as well as several genes involved in nitrogen metabolism. A GlnR homolog from Staphylococcus aureus was found to complement a B. subtilis glnR mutant, regulating GS levels and glnRA expression in a nitrogen-dependent manner. In a GS null mutant, S. aureus GlnR was not able to influence glnRA transcription, indicating that the S. aureus protein is able to respond to the same signals as its B. subtilis counterpart. This is the first demonstration of a relationship between GS and GlnR from a heterologous system and suggests the presence of a regulatory network in S. aureus that responds to changes in environmental nitrogen similar to that described for B. subtilis.