Genomic Structure and Diversity of the Chicken Mx Gene

Abstract

The Mx protein, which confers resistance to orthomyxovirus, has been detected in several organisms, and one nonsynonymous substitution (S631N) of the chicken Mx protein has been shown to affect resistant activities to the avian influenza virus in vitro. In the current study, the genomic sequence and polymorphism of the chicken Mx gene are reported. The full length of the chicken Mx gene spans about 21 kb, with 13 exons on chromosome 1 of the chicken genome. A total of 237 single nucleotide polymorphisms were found in the chicken Mx gene by comparison among 4 directly sequenced Mx genomic DNA sequences, and the reference sequence was inferred from the chicken genome project. The genomic diversity of the chicken Mx gene showed large variation in different regions, with the highest diversity in the 5' untranslated region and the lowest in the 3' untranslated region. The genomic structure and variation of sequences gathered here will allow an extensive analysis of the gene function with the aim of improving the antiviral resistance activities of chickens.

Asparagine 631 Variants of the Chicken Mx Protein Do Not Inhibit Influenza Virus Replication in Primary Chicken Embryo Fibroblasts or In Vitro Surrogate Assays

“…Furthermore, a single amino acid substitution (E645R) in the human MxA protein (within the same domain as position 631 of the chicken Mx protein) abolished anti-VSV but not anti-influenza activity, which indicates that virus-specific effector regions exist (43). In view of these observations and the high degree of polymorphism found with the chicken Mx gene (both in coding [19,35] and in the promoter/5Ј untranslated region [18]), there may be value in largescale screening of naturally occurring chicken Mx alleles for anti-influenza activity. We envisage that the minireplicon assays employed in this study could prove particularly efficient for this purpose.…”

“…The Mx genes from the various CEF lines were amplified by reverse transcriptase (RT)-PCR using SuperScript II RT (Invitrogen), oligo(dT) [12][13][14][15][16][17][18] , Pfx polymerase (Invitrogen), and primers 'AvMxNewF' (5Ј TAG AAC AAA CCG GTA GAA CAG CAG AAC ATG AAC AAT CC 3Ј) and 'AvMxNewR' (5Ј AGA TGA CTC GAG CTA CAG AGA CTT AAA GTC TAC CAG 3Ј).…”

Selection of Mx gene genotype as genetic marker for Avian Influenza resistance in Indonesian native chicken

“…Watanabe [3] studied chicken Mx cDNAs from other breeds to see whether these chickens carried resistant or sensitive character of the Mx gene to the VSV/ vesicular stomatities virus infection, as compared with the differential antiviral activity with amino acid substitutions at 15 positions. Only an amino acid substitution at position 631 was identified to determine the difference between the antiviral activity of chicken Mx protein; Asparagine (Asn) corresponded to the positively antiviral activity and serine (ser) corresponded to the negatively antiviral activity [2-4]. The chicken Mx protein spans about 2,118 bp, with 13 exons on chromosome 1 of the chicken genome.…”

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

“…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].…”

“…This may suggest an alternate role for the additional catfish Mx genes. Indeed, certain Mx genes are not currently thought to be antiviral and their exact role is unknown [34]. Human MxB is one of these, where expression of GTPase defective MxB mutants suggests a role for MxB in nucleocytoplasmic trafficking [41].…”