Prediction of genetic mutations of equine influenza virus related to adaptive determination nuclear export ribonucleoprotein complex

Abstract Background Segment eight (08) of equine influenza virus strain (H3N8) encodes for two non-structural proteins: NS1 (non-structural protein number 1) and NS2, also called NEP (nuclear export protein), via alternative splicing of the pre-messenger RNA transcripts. The NS1 inhibits the cell defense system, while the NEP activates the translocation of the ribonucleoprotein complex to the cytoplasm, a key step in viral assembly. Mutations in this protein could influence viral multiplication. Results In this present study, we used computational and in silico tools to investigate the impact of mutations on the three-dimensional structure of the CRM1 of NEP proteins of three equine influenza strains (H3N8) isolated in Morocco (A/equine/Nador/1/1997 (H3N8), A/equine/Essaouira/2/2004 (H3N8), and A/equine/Essaouira/3/2004 (H3N8)). Compared to the reference strain, the two strains of Essaouira showed no mutations in the domain-binding CRM1 of the NEP protein, while the A/equine/Nador/1/1997 strain (H3N8) had two mutations at the T/33/I and Q/34/R residues. These two mutations corresponded to adaptation phenomenon of the equine cellular environment, since they enhance the interaction between the protein NEP and CRM1 proteins with a greater affinity compared to the reference strain. Conclusion The three-dimensional modification of the NEP protein of the A/equine/Nador/1/1997 strain further facilitates nucleocytoplasmic trafficking in equine species.