Arenaviridae exoribonuclease presents genomic RNA edition capacity

Elsie Yekwa; Chutima Aphibanthammakit; Xavier Carnec; Bruno Coutard; Caroline Picard; Bruno Canard; Sylvain Baize; François Ferron

In order to investigate the substrate requirement for NP-exo MOPV, and NP-exo LCMV , we tested their activities on different RNA substrates HP4, A30 (poly A) and LE19. All these single stranded RNA ( ss RNA) forms several types of secondary structures RNA, which were predicted using Mfold server [59] (S2A Fig). The ExoN assay confirms and extends findings shown in Fig 1, i.e that NP-exo MOPV and NP-exo LCMV cleave RNA substrates whose 3' ends are engaged into a double stranded structure (Fig 3) , consistent with a strict specific double stranded RNA requirement. It is particularly striking in the case of LE19 : at time 0, we observed the 3 species of secondary structures (migration for type A : 19 , B: 18 and C : 17 nucleotides respectively) and with time the top band-product disappears to the profit of an RNA of 17 nucleotides. We observed that NP-exo seems to be partly active on small secondary structure ds RNA but is inactive on ss RNA ( Fig 3) .