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The IscR stability element is a conserved secondary structure found in the intergenic regions of iscRSUA polycistronic mRNA. This secondary structure prevents the degradation of the iscR mRNA.
| iscR stability element | |
|---|---|
 Secondary structure of iscR stability element RNA | |
| Identifiers | |
| Symbol | iscRS |
| Rfam | RF01517 |
| Other data | |
| RNA type | Cis-regulatory element |
| Domain(s) | Enterobacteriales |
| PDB structures | PDBe |
The iscRSUA operon encodes for the proteins required in iron–sulfur cluster biosynthesis where the expression of this operon is regulated by RyhB and iscR, a transcription repressor.[1][2][3] Under sufficient iron conditions RyhB binds to iscRSUA mRNA and promotes the degradation of the mRNA located downstream of iscR. Scanning the intergenic regions of this polycistronic mRNA and using Mfold software a secondary structure was predicted within the intergenic region between iscR and iscS and later confirmed by lead acetate probing.[4] Mutations that disrupt this secondary structure resulted in the degradation of iscR mRNA after RyhB binding. 3′ RACE analysis of the iscR mRNA fragment identified the intergenic RNA at the 3′ end. These results suggest that this intergenic RNA element acts as an iscR mRNA stability element by protecting iscR from exonuclease degradation.
References
edit- ^ Massé E, Escorcia FE, Gottesman S (October 2003). "Coupled degradation of a small regulatory RNA and its mRNA targets in Escherichia coli" (Free full text). Genes & Development. 17 (19): 2374–2383. doi:10.1101/gad.1127103. PMC 218075. PMID 12975324.
- ^ Massé E, Vanderpool CK, Gottesman S (October 2005). "Effect of RyhB small RNA on global iron use in Escherichia coli" (Free full text). Journal of Bacteriology. 187 (20): 6962–6971. doi:10.1128/JB.187.20.6962-6971.2005. PMC 1251601. PMID 16199566.
- ^ Lauhon CT (December 2002). "Requirement for IscS in biosynthesis of all thionucleosides in Escherichia coli" (Free full text). Journal of Bacteriology. 184 (24): 6820–6829. doi:10.1128/JB.184.24.6820-6829.2002. PMC 135461. PMID 12446632.
- ^ Desnoyers G, Morissette A, Prévost K, Massé E (June 2009). "Small RNA-induced differential degradation of the polycistronic mRNA iscRSUA". The EMBO Journal. 28 (11): 1551–1561. doi:10.1038/emboj.2009.116. PMC 2693151. PMID 19407815.
Further reading
edit- Deng Z, Liu Z, Bi Y, Wang X, Zhou D, Yang R, Han Y (2014). "Rapid degradation of Hfq-free RyhB in Yersinia pestis by PNPase independent of putative ribonucleolytic complexes". BioMed Research International. 2014: 798918. doi:10.1155/2014/798918. PMC 4003864. PMID 24818153.