Genomic structure, promoter analysis, and expression of the porcine (Sus scrofa) Mx1 gene

Abstract

Allelic polymorphisms at the mouse Mx1 locus affect the probability of survival after experimental influenzal disease, raising the possibility that marker-assisted selection using the homologous locus could improve the innate resistance of pigs to natural influenza infections. Several issues need to be resolved before efficient large scale screening of the allelic polymorphism at the porcine (Sus scrofa) Mx1 locus can be implemented. First, the Mx1 genomic structure has to be established and sufficient flanking intronic sequences have to be gathered to enable simple PCR amplification of the coding portions of the gene. Then, a basic knowledge of the promoter region needs to be obtained as an allelic variation there can significantly alter absolute levels and/or tissue-specificity of MX protein expression. The results gathered here show that the porcine Mx1 gene and promoter share the major structural and functional characteristics displayed by their homologs described in cattle, mouse, chicken, and man. The crucial function of the proximal interferon-sensitive response elements motif for gene expression is also demonstrated. The sequence data compiled here will allow an extensive analysis of the polymorphisms present among the widest spectrum possible of porcine breeds with the aim to identify an Mx1 allele providing antiviral resistance.

Genomic organisation of the channel catfish Mx1 gene and characterisation of multiple channel catfish Mx gene promoters

“…However, similarly to the Fugu and zebrafish, the catfish promoters do not appear to possess a TATA box or Sp1 site. Like the channel catfish Mx1 promoter the chicken [37], porcine [31] and bovine [30] Mx promoters all possess a putative NF-kb site, in contrast with other fish Mx promoters characterised to date.…”

“…NF-kb transcription factors have been identified in the bovine [30], porcine [31] and human [39] Mx promoters. However, these factors are not stimulated by tumour necrosis factor a or lipopolysaccharide and may be non-functional [39].…”

“…Not only is it smaller in size but it also contains slightly fewer exons. The bovine [30] and porcine [31] Mx1 genes both contain 15 exons, the mouse 14 exons [32], the human 17 exons [33], and the chicken 13 exons [34]. The organisation of the catfish Mx1 gene is similar to the Fugu, which also has 12 exons and 11 introns [28].…”

Construction of transgenic swine with induced expression of Cre recombinase

“…Porcine models are better for human disease research than a number of other laboratory animal model (Hammer et al, 1985;Miller et al, 1989;Schwenk et al, 1998;Forsberg et al, 2002;Lai et al, 2002;Raffai and Weisgraber, 2002;Tucker et al, 2002;Thomas et al, 2006;Fujimura et al, 2008). In this study, we combined the specificity of the Cre-loxP recombination system with the research model characteristics of swine.…”

Polymorphisms of the chicken antiviral <i>MX</i> gene

“…The consensus sequences detected in all other IFN-inducible promoters were also found in the mouse Mx1 gene. Subsequently, the existence of a promoter region was reported in other Mx genes such as human MXA (Horisberger et al, 1990;Chang et al, 1991), chicken MX (Schumacher et al, 1994), mouse Mx2 (Asano et al, 2003), bovine MX1 (Gerardin et al, 2004) and porcine MX1 (Thomas et al, 2006). Their promoter regions contained consensus sequences such as IFN-stimulating response element (ISRE), Sp1 binding site, NF-B and IL-6 response element.…”