FnrS RNA
| FnrS | |
|---|---|
| File:FnrS SScons.png Conserved secondary structure of FnrS RNA. The colour of nucleotides indicate their conservation within the family. | |
| Identifiers | |
| Symbol | FnrS |
| Rfam | RF01796 |
| Other data | |
| RNA type | Gene |
| Domain | Enterobacteriaceae |
| PDB structures | PDBe |
FnrS RNA is a family of Hfq-binding small RNA whose expression is upregulated in response to anaerobic conditions. It is named FnrS because its expression is strongly dependent on fumarate and nitrate reductase regulator (FNR), a direct oxygen availability sensor.[1][2]
A conserved intergenic region between genes ydaN and dbpA was predicted to encode an sRNA, adjacent to where another non-coding RNA (C0343) has been identified.[3] However, northern blot analysis of this 477bp sequence yielded no results.[4] A subsequent tiling array analysis sequencing Hfq-binding sRNA found that the Watson strand did indeed encode an sRNA.[1]
Gene regulation
[edit | edit source]FnrS has been shown to downregulate 32 different mRNAs in Enterobacteria, in 15 of these cases it does so by base-pairing with the mRNA transcript.[1] The majority of genes downregulated by FnrS are required for aerobic metabolism or the oxidative stress response.[2] Some of the genes downregulated by FnrS are:[1]
- adhP - an alcohol dehydrogenase involved in metabolism
- cydD - zinc sensitive ATP-binding component of cytochrome-related transport[5]
- mqo - membrane associated malate:quinone oxidoreductase which operates in the citric acid cycle[6]
- sodB/A - a superoxide dismutase which aids with oxygen stress resistance[7]
- ygiW - a hypothetical outer membrane protein[8]
A study incorporating comparative target prediction and subsequent experimental verification of selected predictions, suggests that FnrS might be a more global regulator in Escherichia coli. It is predicted to control several transcription factors. These include the verified targets marA and IscR.[9] MarA activates genes involved in the resistance to superoxide,[10] which might not be necessary at the anaerobic conditions where FnrS is expressed. IscR regulates genes for iron-sulfur-cluster containing or biogenesis proteins.[11] FnrS might be involved in the observed O2 dependent expression of the IscR regulon.[11] Further targets of FnrS are nagZ and sdhA.[9]
There is also evidence to suggest that the expression of FnrS is regulated by the RcsCDB signalling system in Salmonella enterica.[12]
References
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- ^ EntrezGene 944953
- ^ EntrezGene 8872708
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Further reading
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- Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).