The Old World (OW) arenavirus complex includes several species of rodent-borne viruses, some of which (i.e., Lassa virus, LASV and Lymphocytic choriomeningitis virus, LCMV) cause human diseases. Most LCMV and LASV infections are caused by rodent-to-human transmissions. Thus, viral evolution is largely determined by events that occur in the wildlife reservoirs. We used a set of human- and rodent-derived viral sequences to investigate the evolutionary history underlying OW arenavirus speciation, as well as the more recent selective events that accompanied LASV spread in West Africa. We show that the viral RNA polymerase (L protein) was a major positive selection target in OW arenaviruses and during LASV out-of-Nigeria migration. No evidence of selection was observed for the glycoprotein, whereas positive selection acted on the nucleoprotein (NP) during LCMV speciation. Positively selected sites in L and NP are surrounded by highly conserved residues, and the bulk of the viral genome evolves under purifying selection. Several positively selected sites are likely to modulate viral replication/transcription. In both L and NP, structural features (solvent exposed surface area) are important determinants of site-wise evolutionary rate variation. By incorporating several rodent-derived sequences, we also performed an analysis of OW arenavirus codon adaptation to the human host. Results do not support a previously hypothesized role of codon adaptation in disease severity for non-Nigerian strains. In conclusion, L and NP represent the major selection targets and possible determinants of disease presentation; these results suggest that field surveys and experimental studies should primarily focus on these proteins.
Evolutionary analysis of Old World arenaviruses reveals a major adaptive contribution of the viral polymerase / C. Pontremoli, D. Forni, R. Cagliani, U. Pozzoli, S. Riva, I.G. Bravo, M. Clerici, M. Sironi. - In: MOLECULAR ECOLOGY. - ISSN 0962-1083. - 26:19(2017), pp. 5173-5188.
|Titolo:||Evolutionary analysis of Old World arenaviruses reveals a major adaptive contribution of the viral polymerase|
PONTREMOLI, CHIARA (Primo) (Corresponding)
FORNI, DIEGO (Secondo)
CLERICI, MARIO SALVATORE (Penultimo)
|Parole Chiave:||codon adaptation; Old World arenaviruses; positive selection; protein evolution; rodents; viral polimerase; Africa, Western; amino acid sequence; arenaviruses, Old World; DNA-directed RNA polymerases; Lassa virus; lymphocytic choriomeningitis virus; phylogeny; protein structure, tertiary; viral proteins; biological evolution; selection, genetic; ecology, evolution, behavior and systematics; genetics|
|Settore Scientifico Disciplinare:||Settore MED/04 - Patologia Generale|
Settore BIO/18 - Genetica
|Data di pubblicazione:||2017|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1111/mec.14282|
|Appare nelle tipologie:||01 - Articolo su periodico|