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ANR regulateurs procaryotiques et virulence

Abstract : During my thesis, I was interested by two procaryotic regulatory RNA. The first, RNAIII, is a multifunctionnal RNA which regulates the expression of virulence gene in Staphylococcus aureus. The second, CopA, is stricly complementary to its target and regulates the rate of plasmid R1 replication. RNAIII inhibits the expression of adhesins and activates the synthesis of toxins at the end of exponential growth phase. We have shown that the 3' end domain of RNAIII is necessary and sufficient for the inhibition of the expression of two proteins at the post-transcriptional level, the protein A and SA1000. The binding of RNAIII to its targets is initiated by a loop-loop interaction which is rapidly converted to a full duplex. This duplex is the target of RNase III to induce the rapid degradation of the mRNA. We have also shown that Hfq protein is a ligand of RNAIII and the function of this interaction in the virulence of S. aureus is under investigation.
The antisense RNA CopA regulates bacterial plasmid R1 replication by controlling the rate of synthesis of the RepA initiator protein. The binding of CopA to its target, repA mRNA, inhibits the synthesis of RepA and promotes the degradation of the mRNA. The interaction between the two RNA leds to the formation of an irreversible complex. This complex is not a full duplex but contains a four-way junction stabilized by a long intermolecular helix, helix C. We have shown that the structures of both RNA have evolved to block the progression from the irreversible complex to the full duplex. Moreover, we have shown that in the irreversible complex, helix C is recognized by RNase III at preferentials sites.
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https://tel.archives-ouvertes.fr/tel-00139058
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Submitted on : Thursday, March 29, 2007 - 10:10:26 AM
Last modification on : Thursday, November 19, 2020 - 2:16:11 PM
Long-term archiving on: : Friday, September 21, 2012 - 1:35:38 PM

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  • HAL Id : tel-00139058, version 1

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Eric Huntzinger. ANR regulateurs procaryotiques et virulence. Biochimie [q-bio.BM]. Université Louis Pasteur - Strasbourg I, 2005. Français. ⟨tel-00139058⟩

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