CrfA SScons.png
Conserved secondary structure of CrfA RNA.
Symbol CrfA
Other data
Domain(s) Caulobacter

CrfA RNA (Caulobacter response to famine RNA) is a family of non-coding RNAs found in Caulobacter crescentus. CrfA is expressed upon carbon starvation and is thought to activate 27 genes.[1] It was originally identified along with 26 other non-coding RNAs using a tiled Caulobacter microarray protocol specifically aimed at detecting small RNAs.[2]

CrfA RNA is one of only 8 putative ncRNAs conserved in the closely related Caulobacter sp. K31.[1]

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.[1]

Affymetrix microarrays were then used to analyse changes in the transcriptome in response to increased CrfA. Seven affacted gene products were TonB-dependent receptors, outer membrane proteins which facilitate the uptake of external substrate.[3] The upregulation of these proteins could increase the carbon uptake during starvation. Another CrfA regulated gene (EntrezGene CC_1363) 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.[1]

σ54 regulates many other proteins involved in the carbon starvation response at the level of transcription.[4]


Further reading

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