Arenaviridae exoribonuclease presents genomic RNA edition capacity

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

Another observation that concurs to the "limited proof-reading" mechanism is the difference of Ribavirin efficiency on Arenaviridae and Coronaviridae. Ribavirin is the only drug so far administered on large scale and having demonstrated a decrease of mortality rates up to 5%, if administered within the first 6 days of arenaviral illness [73] . On the other hand, Ribavirin is ineffective against coronaviruses [74, 75] , as nsp14 ExoN domain excises the nucleotide analogue [51] . It is likely, that for Arenaviridae, the ExoN activity involved in a "limited proof-reading" mechanism remains as a trace of its past common ancestor with Coronaviridae. The critical problem of genomic stability being solved, either by the conservation of the "original" function of the ExoN for Coronaviridae, or by genome segmentation for Arenaviridae.