RNAIII

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RNAIII is a stable 514 nt regulatory RNA transcribe d by the P3 promoter of the Staphylococcus aureus quorum-sensing agr system [1] [2] ). It is the major effector of the agr regulon, which controls the expression of many S. aureus genes encoding exoproteins and cell wall associated proteins plus others encoding regulatory proteins [3] [4]  The RNAIII transcript also encodes the 26 amino acid δ-haemolysin (Staphylococcus aureus delta toxin) peptide (Hld). [5] RNAIII contains many stem loops, most of which match the Shine-Dalgarno sequence involved in translation initiation of the regulated genes. [5] Some of these interactions are inhibitory, others stimulatory; among the former is the regulatory protein Rot. [6] [7] In vitro, RNAIII is expressed post exponentially, inhibiting translation of the surface proteins, notably protein A, while stimulating that of the exoproteins, many of which are tissue-degrading enzymes or cytolysins. [8] Among the latter is the important virulence factor, α-hemolysin (or alpha toxin) (Hla), whose translation RNAIII activates by preventing the formation of an inhibitory foldback loop in the hla mRNA leader. [9]

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References

  1. Novick RP, Ross HF, Projan SJ, Kornblum J, Kreiswirth B, Moghazeh S (October 1993). "Synthesis of staphylococcal virulence factors is controlled by a regulatory RNA molecule". The EMBO Journal. 12 (10): 3967–75. doi:10.1002/j.1460-2075.1993.tb06074.x. PMC   413679 . PMID   7691599.
  2. Waters LS, Storz G (February 2009). "Regulatory RNAs in bacteria". Cell. 136 (4): 615–28. doi:10.1016/j.cell.2009.01.043. PMC   3132550 . PMID   19239884.
  3. Janzon L, Arvidson S (May 1990). "The role of the delta-lysin gene (hld) in the regulation of virulence genes by the accessory gene regulator (agr) in Staphylococcus aureus". The EMBO Journal. 9 (5): 1391–9. doi:10.1002/j.1460-2075.1990.tb08254.x. PMC   551825 . PMID   2328718.
  4. Novick RP (June 2003). "Autoinduction and signal transduction in the regulation of staphylococcal virulence". Molecular Microbiology. 48 (6): 1429–49. doi: 10.1046/j.1365-2958.2003.03526.x . PMID   12791129. S2CID   6847208.
  5. 1 2 Benito Y, Kolb FA, Romby P, Lina G, Etienne J, Vandenesch F (May 2000). "Probing the structure of RNAIII, the Staphylococcus aureus agr regulatory RNA, and identification of the RNA domain involved in repression of protein A expression". RNA. 6 (5): 668–79. doi:10.1017/S1355838200992550. PMC   1369947 . PMID   10836788.
  6. Geisinger E, Adhikari RP, Jin R, Ross HF, Novick RP (August 2006). "Inhibition of rot translation by RNAIII, a key feature of agr function". Molecular Microbiology. 61 (4): 1038–48. doi: 10.1111/j.1365-2958.2006.05292.x . PMID   16879652. S2CID   229424.
  7. Boisset S, Geissmann T, Huntzinger E, Fechter P, Bendridi N, Possedko M, et al. (June 2007). "Staphylococcus aureus RNAIII coordinately represses the synthesis of virulence factors and the transcription regulator Rot by an antisense mechanism". Genes & Development. 21 (11): 1353–66. doi:10.1101/gad.423507. PMC   1877748 . PMID   17545468.
  8. Dunman PM, Murphy E, Haney S, Palacios D, Tucker-Kellogg G, Wu S, et al. (December 2001). "Transcription profiling-based identification of Staphylococcus aureus genes regulated by the agr and/or sarA loci". Journal of Bacteriology. 183 (24): 7341–53. doi:10.1128/JB.183.24.7341-7353.2001. PMC   95583 . PMID   11717293.
  9. Morfeldt E, Taylor D, von Gabain A, Arvidson S (September 1995). "Activation of alpha-toxin translation in Staphylococcus aureus by the trans-encoded antisense RNA, RNAIII". The EMBO Journal. 14 (18): 4569–77. doi:10.1002/j.1460-2075.1995.tb00136.x. PMC   394549 . PMID   7556100.

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