Molecular identification and comparative transcriptional analysis of myxovirus resistance GTPase (Mx) gene in goose (Anser cygnoide) after H9N2 AIV infection.

Interferon (IFN)-induced myxovirus resistance (Mx) GTPases belong to the family of dynamin-like GTPases and control a diverse range of viruses. In this study, the identified goose Mx (goMx) mRNA is 2009bp long, shares partially conserved exons with other homologues, and shares highly conserved domains in its primary structure. The amino acid position 629 (629aa) of the goMx protein was identified as serine (Ser), in contrast to the Ser located at 631aa in chicken Mx, which is considered to be responsible for the lack of chicken Mx antiviral activity. In addition, the goMx 142aa residue in the dynamin family signature differs from that of other functional Mx proteins. Transcriptional analysis revealed that goMx was mainly expressed in the digestive, respiratory and immune systems in an age-specific manner. GoMx transcript levels in goose peripheral blood mononuclear cells (PBMCs) were found to be significantly up-regulated by various agonists and avian viruses. Furthermore, a time course study of the effects of H9N2 avian influenza virus (AIV) on goMx expression in infected goslings suggested that H9N2 AIV affected goMx expression. However, significant changes in goMx expression were observed in the trachea, lung and small intestine of infected birds. Altogether, these results indicate that goMx protein may have acquired its broad antiviral activity by changing only a few amino acids at select sites, even as it shares a conserved architectures with species.