CrfA RNA

Carbon starvation response

CrfA was found to be upregulated 10-fold in C. crescentus when glucose was deprived in a minimal medium. Further experimentation found the response to be specific to carbon deprivation; its expression was not increased when phosphate or nitrogen were limiting factors.

Affymetrix microarrays were then used to analyse changes in the transcriptome in response to increased CrfA. Seven affected gene products were TonB-dependent receptors, outer membrane proteins which facilitate the uptake of external substrate. The upregulation of these proteins could increase the carbon uptake during starvation. Another CrfA regulated gene () is thought to encode a proton pump powered by pyrophosphate hydrolysis. Increasing production of this protein could enable the cell to maintain its electrochemical gradient and power ATP synthesis during carbon starvation.

σ54 regulates many other proteins involved in the carbon starvation response at the level of transcription.

References

References

1. (September 2010). "CrfA, a Small Noncoding RNA Regulator of Adaptation to Carbon Starvation in Caulobacter crescentus". J. Bacteriol..
2. (May 2008). "Small non-coding RNAs in Caulobacter crescentus". Mol. Microbiol..
3. Koebnik R. (August 2005). "TonB-dependent trans-envelope signalling: the exception or the rule?". Trends Microbiol..
4. (February 2010). "Global regulation of gene expression and cell differentiation in Caulobacter crescentus in response to nutrient availability". J. Bacteriol..