Fidelity variants of RNA dependent RNA polymerases uncover an indirect, mutagenic activity of amiloride compounds.

Laura Levi (1) , Nina Gnadig (1) , Stéphanie Beaucourt (1) , Malia Mcpherson (1) , Bruno Baron (2) , Jamie Arnold (3) , Marco Vignuzzi (1)

1 Populations virales et Pathogenèse
2 Biophysique des Macromolécules et de leurs Interactions
3 Department of Biochemistry and Molecular Biology

In a screen for RNA mutagen resistance, we isolated a high fidelity RNA dependent RNA polymerase (RdRp) variant of Coxsackie virus B3 (CVB3). Curiously, this variant A372V is also resistant to amiloride. We hypothesize that amiloride has a previously undescribed mutagenic activity. Indeed, amiloride compounds increase the mutation frequencies of CVB3 and poliovirus and high fidelity variants of both viruses are more resistant to this effect. We hypothesize that this mutagenic activity is mediated through alterations in intracellular ions such as Mg²+ and Mn²+, which in turn increase virus mutation frequency by affecting RdRp fidelity. Furthermore, we show that another amiloride-resistant RdRp variant, S299T, is completely resistant to this mutagenic activity and unaffected by changes in ion concentrations. We show that RdRp variants resist the mutagenic activity of amiloride via two different mechanisms: 1) increased fidelity that generates virus populations presenting lower basal mutation frequencies or 2) resisting changes in divalent cation concentrations that affect polymerase fidelity. Our results uncover a new antiviral approach based on mutagenesis.

Domains: Life Sciences [q-bio]; Microbiology and Parasitology; Virology

Laura Levi, Nina Gnadig, Stéphanie Beaucourt, Malia Mcpherson, Bruno Baron, et al.. Fidelity variants of RNA dependent RNA polymerases uncover an indirect, mutagenic activity of amiloride compounds.. PLoS Pathogens, 2010, 6 (10), pp.e1001163. ⟨10.1371/journal.ppat.1001163⟩. ⟨pasteur-00530598⟩