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Abstract

Much is known about the antiviral activity of Mx proteins in species such as mouse and human. In the mouse, loss of resistability to influenza virus has been shown to be due to specific polymorphisms in the Mx gene. This gene is therefore an interesting candidate gene for disease resistance in farm animals. The porcine Mx1 gene has already been identified and characterized based on its homology with mouse Mx1; however, until now no evidence of polymorphisms in the porcine gene has been reported. In this study, we have found two new polymorphisms in exon 14 of porcine Mx1 by DNA sequencing and confirmed their presence in different breeds, using polymerase chain reaction (PCR)-restriction fragment length polymorphisms (RFLP) with NarI and NaeI restriction enzymes. On the basis of the deduced amino acid sequence, one allele contains a deletion that may result in a frameshift to yield several amino acid substitutions and extension of the carboxyl terminal region of Mx1 protein. The deletion allele, Mx1c, was found to be segregating in Landrace, Berkshire, Duroc, Hampshire, and Yucatan miniature pig. A second point mutation, Mx1b, was detected in Meishan and two Vietnamese native pig breeds. All other breeds tested were fixed for the Mx1a allele that is identical to the sequence reported previously. It will be interesting to determine if the Mx1c deletion is associated with variation in resistance to the myxovirus family in the pig.

RNA Deep Sequencing Reveals Novel Candidate Genes and Polymorphisms in Boar Testis and Liver Tissues with Divergent Androstenone Levels

“…Location of IFIT2 gene on SSC14 incorporated the QTL affecting androstenone in Yorkshire pig [56] and subjective pork flavour in Large White and Meishan pigs [24]. MX1 is an interesting candidate gene for disease resistance in farm animals [57] but this study first identifies association with boar taint compounds. No study investigated association of CYP7A1 with boar taint compounds.…”

New polymorphism of the influenza virus resistance Mx1 gene in Iberian domestic pigs

“…This new deletion extends 1 nucleotide upstream and 16 downstream the previous 11bp-deletion and results in a frameshift which is expected to encode a protein with 9 amino acid substitutions and a 20 amino acid extension compared to the wild type (p.Arg655GlufsX29). Most of the mutations localized in C-terminal domain of MX proteins appear to abolish antiviral effect (Morozumi et al, 2001; Nakajima et al, 2007). Therefore, it could be expected that in this new isoform the anti-influenza activity could be also affected.…”

“…The analysis of the Mx1 gene sequence has allowed the identification of polymorphisms in most of the species resulting in differential antiviral activity of the distinct isoforms (Haller et al, 1987). In pig, two main deletions have been identified; 3bp in exon 13, which produces the lost of the serine residue at amino acid 565 (AB259856:g.1778_1810del3, p.Ser565del), and 11bp in exon 14, which leads to a frameshift with 8 amino acid substitutions and a 23 amino acid extension at the C-terminal region of the MX1 protein (c.2131_2141del11, referred to GenBank DQ095779; p.Arg656GlnfsX31), where the antiviral effect is located (Morozumi et al, 2001; Nakajima et al, 2007). Mutations in this region in mouse have been related to increased susceptibility to influenza virus infection (Staeheli et al, 1988).…”

Molecular cloning, polymorphism, and functional activity of the bovine and water buffalo Mx2 gene promoter region

“…The existence of more than one isoform of the Mx gene in farm animals, including poultry (Bazzigher et al 1993; Schumacher et al 1994; Ko et al 2002), porcine (Morozumi et al 2001; Asano et al 2002), ovine (Charleston and Stewart 1993), and bovine (Ellinwood et al 1998), strength the probability of implementing genetic selection programs to heighten productivity efficiency in the livestock industry. In addition, association of the Mx protein induction with viral infections highlighted the possibility of using the protein as a marker for acute viral infection to monitor a disease state in livestock (Muller-Doblies et al 2002, 2004).…”