NtrC

NtrC (Nitrogen regulatory protein C) is the name of the protein necessary for the prokaryotic regulation transcription factor sigma N (sigma 54) to form an open complex with RNA polymerase in order to activate glnA transcription. The closed -> open conformational change of the sigma N-RNA polymerase complex around the glutamine synthetase gene promoter requires ATP and involves the formation of a loop between the enhancer and the promoter regions, which may be facilitated by DNA-bending proteins (such as IHF).^[1] The NtrC proteins bind at two sites located -160 and -80 upstream from the point of gene transcription.

References

1. Carmona, M; Magasanik, B (1996). "Activation of transcription at sigma 54-dependent promoters on linear templates requires intrinsic or induced bending of the DNA". J Mol Biol. 261 (3): 348–56. doi:10.1006/jmbi.1996.0468. PMID 8780778.

• Lecture notes, Molecular Genetics 3 at the University of Edinburgh autumn 2006