SgrS RNA
RNA family
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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.[2] It has been proposed that SgrT exerts its effects through regulation of the glucose transporter, PtsG.[6][7]
| SgrS RNA | |
|---|---|
Predicted secondary structure and sequence conservation of SgrS | |
| Identifiers | |
| Symbol | SgrS |
| Rfam | RF00534 |
| Other data | |
| RNA type | Gene; antisense |
| Domain | Bacteria |
| GO | GO:0032057 GO:0043488 GO:0030371 |
| SO | SO:0000655 |
| PDB structures | PDBe |
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]
