1. |
Schumacher J.♦, Behrends V.♦, Pan Z.♦, Brown D.R.♦, Heydenreich F.♦, Lewis M.R.♦, Bennett M.H.♦, Razzaghi B.♦, Komorowski M., Barahona M.♦, Stumpf M.P.H.♦, Wigneshweraraj S.♦, Bundy J.G.♦, Buck M.♦, Nitrogen and carbon status are integrated at the transcriptional level by the nitrogen regulator NtrC in vivo,
mBio, ISSN: 2150-7511, DOI: 10.1128/mBio.00881-13, Vol.4, pp.00881-1-13, 2013Abstract: Nitrogen regulation in Escherichia coli is a model system for gene regulation in bacteria. Growth on glutamine as a sole nitrogen source is assumed to be nitrogen limiting, inferred from slow growth and strong NtrB/NtrC-dependent gene activation. However, we show that under these conditions, the intracellular glutamine concentration is not limiting but 5.6-fold higher than in ammonium-replete conditions; in addition, α-ketoglutarate concentrations are elevated. We address this glutamine paradox from a systems perspective. We show that the dominant role of NtrC is to regulate glnA transcription and its own expression, indicating that the glutamine paradox is not due to NtrC-independent gene regulation. The absolute intracellular NtrC and GS concentrations reveal molecular control parameters, where NtrC-specific activities were highest in nitrogen-starved cells, while under glutamine growth, NtrC showed intermediate specific activity. We propose an in vivo model in which α-ketoglutarate can derepress nitrogen regulation despite nitrogen sufficiency. Affiliations:
Schumacher J. | - | Imperial College London (GB) | Behrends V. | - | Imperial College London (GB) | Pan Z. | - | Imperial College London (GB) | Brown D.R. | - | Imperial College London (GB) | Heydenreich F. | - | Imperial College London (GB) | Lewis M.R. | - | Imperial College London (GB) | Bennett M.H. | - | Imperial College London (GB) | Razzaghi B. | - | Imperial College London (GB) | Komorowski M. | - | IPPT PAN | Barahona M. | - | Imperial College London (GB) | Stumpf M.P.H. | - | Imperial College London (GB) | Wigneshweraraj S. | - | Imperial College London (GB) | Bundy J.G. | - | Imperial College London (GB) | Buck M. | - | Imperial College London (GB) |
| |