GBP6: differential expression in pulmonary alveolar macrophages under PRRSV infection and association with blood parameters of its missense mutation

The GBP6 gene belongs to the gene family of interferon-gamma inducible GTPases, and is located in a previously characterized QTL region of porcine reproductive and respiratory syndrome virus (PRRSV) resistance in SSC4. In the current study, RT-PCR assay revealed that the GBP6 gene was widely distributed but highly expressed in spleen and lung. Under PRRSV infection, the GBP6 gene was up-regulated and differentially expressed in the pulmonary alveolar macrophages (PAMs) of Large White and Tongcheng pigs. Multiple sequences alignment and phylogenetic analysis revealed that GBP6 is highly conserved across species. We validated and analyzed the polymorphism of a missense mutation (n.932A>G, rs322187731) in the F2 resource population of Duroc x Erhualian, which changed the Valine (V) to Methionine (M) in the 300th residue of porcine GBP6. Through a linear mixed effects model, the polymorphism of the mutation (n. 932A>G, rs322187731) was significantly associated with five haematological traits, namely platelet count at 20 days (PLT-20), plateletcrit at 20 days (PCT-20), white blood cell at 33 days (WBC-33), neutrophil count at 33 days (NE-33) and red blood cell count at 80 days (RBC-80). The findings presented here provide basic information for the function and possible involvement of the GBP6 gene in immune regulation and disease resistance.