SgrS RNA explained

SgrS RNA
Symbol:	SgrS
Rfam:	RF00534
Rna Type:	Gene antisense
Tax Domain:	Bacteria

SgrS (sugar transport-related sRNA, previously named ryaA)^[1] is a 227 nucleotide small RNA that is activated by SgrR in Escherichia coli during glucose-phosphate stress. The nature of glucose-phosphate stress is not fully understood, but is correlated with intracellular accumulation of glucose-6-phosphate.^[2] SgrS helps cells recover from glucose-phosphate stress by base pairing with ptsG mRNA (encoding the glucose transporter) and causing its degradation in an RNase E dependent manner.^{[3] [4]} Base pairing between SgrS and ptsG mRNA also requires Hfq, an RNA chaperone frequently required by small RNAs that affect their targets through base pairing.^[5] The inability of cells expressing sgrS to create new glucose transporters leads to less glucose uptake and reduced levels of glucose-6-phosphate. SgrS is an unusual small RNA in that it also encodes a 43 amino acid functional polypeptide, SgrT, which helps cells recover from glucose-phosphate stress by preventing glucose uptake. The activity of SgrT does not affect the levels of ptsG mRNA of PtsG protein. It has been proposed that SgrT exerts its effects through regulation of the glucose transporter, PtsG.^{[6] [7]}

SgrS was originally discovered in E. coli but homologues have since been identified in other Gammaproteobacteria such as Salmonella enterica and members of the genus Citrobacter.^[8] A comparative genomics based target prediction approach that employs these homologs, has been developed and was used to predict the SgrS target, ptsI (b2416), which was subsequently verified experimentally.^[9]

Further reading

• Vanderpool CK . Physiological consequences of small RNA-mediated regulation of glucose-phosphate stress . Current Opinion in Microbiology . 10 . 2 . 146–51 . April 2007 . 17383224 . 10.1016/j.mib.2007.03.011 .
• Aiba H . Mechanism of RNA silencing by Hfq-binding small RNAs . Current Opinion in Microbiology . 10 . 2 . 134–9 . April 2007 . 17383928 . 10.1016/j.mib.2007.03.010 .
• Sun Y, Vanderpool CK . Physiological consequences of multiple-target regulation by the small RNA SgrS in Escherichia coli . Journal of Bacteriology . 195 . 21 . 4804–15 . November 2013 . 23873911 . 3807494 . 10.1128/JB.00722-13 .
• Bobrovskyy M, Vanderpool CK . The small RNA SgrS: roles in metabolism and pathogenesis of enteric bacteria . Frontiers in Cellular and Infection Microbiology . 4 . 61 . 2014 . 24847473 . 4021124 . 10.3389/fcimb.2014.00061 . free .
• Papenfort K, Sun Y, Miyakoshi M, Vanderpool CK, Vogel J . Small RNA-mediated activation of sugar phosphatase mRNA regulates glucose homeostasis . Cell . 153 . 2 . 426–37 . April 2013 . 23582330 . 4151517 . 10.1016/j.cell.2013.03.003 .

External links

• • sRNAmap page for SgrS RNA
• Vanderpool Lab
• Aiba Lab

Notes and References

1. Vanderpool CK, Gottesman S . Involvement of a novel transcriptional activator and small RNA in post-transcriptional regulation of the glucose phosphoenolpyruvate phosphotransferase system . Molecular Microbiology . 54 . 4 . 1076–89 . November 2004 . 15522088 . 10.1111/j.1365-2958.2004.04348.x . 24804508 . free .
2. Wadler CS, Vanderpool CK . A dual function for a bacterial small RNA: SgrS performs base pairing-dependent regulation and encodes a functional polypeptide . Proceedings of the National Academy of Sciences of the United States of America . 104 . 51 . 20454–9 . December 2007 . 18042713 . 2154452 . 10.1073/pnas.0708102104 . free .
3. Vanderpool CK, Gottesman S . The novel transcription factor SgrR coordinates the response to glucose-phosphate stress . Journal of Bacteriology . 189 . 6 . 2238–48 . March 2007 . 17209026 . 1899371 . 10.1128/JB.01689-06 .
4. Rice JB, Vanderpool CK . The small RNA SgrS controls sugar-phosphate accumulation by regulating multiple PTS genes . Nucleic Acids Research . 39 . 9 . 3806–19 . May 2011 . 21245045 . 3089445 . 10.1093/nar/gkq1219 .
5. Kawamoto H, Koide Y, Morita T, Aiba H . Base-pairing requirement for RNA silencing by a bacterial small RNA and acceleration of duplex formation by Hfq . Molecular Microbiology . 61 . 4 . 1013–22 . August 2006 . 16859494 . 10.1111/j.1365-2958.2006.05288.x . 35533720 . free .
6. Maki K, Morita T, Otaka H, Aiba H . A minimal base-pairing region of a bacterial small RNA SgrS required for translational repression of ptsG mRNA . Molecular Microbiology . 76 . 3 . 782–92 . May 2010 . 20345651 . 10.1111/j.1365-2958.2010.07141.x . 39687800 .
7. Kawamoto H, Morita T, Shimizu A, Inada T, Aiba H . Implication of membrane localization of target mRNA in the action of a small RNA: mechanism of post-transcriptional regulation of glucose transporter in Escherichia coli . Genes & Development . 19 . 3 . 328–38 . February 2005 . 15650111 . 546511 . 10.1101/gad.1270605 .
8. Horler RS, Vanderpool CK . Homologs of the small RNA SgrS are broadly distributed in enteric bacteria but have diverged in size and sequence . Nucleic Acids Research . 37 . 16 . 5465–76 . September 2009 . 19531735 . 2760817 . 10.1093/nar/gkp501 .
9. Wright PR, Richter AS, Papenfort K, Mann M, Vogel J, Hess WR, Backofen R, Georg J . Comparative genomics boosts target prediction for bacterial small RNAs . Proceedings of the National Academy of Sciences of the United States of America . 110 . 37 . E3487-96 . September 2013 . 23980183 . 3773804 . 10.1073/pnas.1303248110 . 2013PNAS..110E3487W . free .