title: Mx mRNA expression and RFLP analysis of rainbow trout Oncorhynchus mykiss genetic crosses selected for susceptibility or resistance to IHNV.
abstract: Three interferon-inducible Mx genes have been identified in rainbow trout Oncorhynchus mykiss and their roles in virus resistance have yet to be determined. In mice, expression of the Mx1 protein is associated with resistance to influenza virus. We report a study to determine whether there was a correlation between the expression of Mx in rainbow trout and resistance to a fish rhabdovirus, infectious hematopoietic necrosis virus (IHNV). A comparison of Mx mRNA expression was made between different families of cultured rainbow trout selected for resistance or for susceptibility to IHNV. A trout-specific Mx cDNA gene probe was used to determine whether there was a correlation between Mx mRNA expression and resistance to the lethal effects of IHNV infection. Approximately 99% of trout injected with a highly virulent strain of the fish rhabdovirus, IHNV, were able to express full length Mx mRNA at 48 h post infection. This is markedly different from the expression of truncated, non-functional Mx mRNA found in most laboratory strains of mice, and the ability of only 25% of wild mice to express functional Mx protein. A restriction fragment length polymorphism (RFLP) assay was developed to compare the Mx locus between individual fish and between rainbow trout genetic crosses bred for IHNV resistance or susceptibility. The assay was able to discriminate 7 distinct RFLP patterns in the rainbow trout crosses. One cross was identified that showed a correlation between homozygosity at the Mx locus and greater susceptibility to IHN-caused mortality.
authors.affiliation: Department of Microbiology, Oregon State University, Corvallis 97331-3804, USA.
authors.forename: G D
authors.initials: GD
authors.lastname: Trobridge
authors.forename: S E
authors.initials: SE
authors.lastname: LaPatra
authors.forename: C H
authors.initials: CH
authors.lastname: Kim
authors.forename: J C
authors.initials: JC
authors.lastname: Leong
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000096:biosynthesis / Q000235:genetics*; D015152:Blotting, Northern / Q000662:veterinary; D015139:Blotting, Southern / Q000662:veterinary; D002460:Cell Line; D003433:Crosses, Genetic; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D005260:Female; D005393:Fish Diseases / Q000235:genetics*; D019204:GTP-Binding Proteins; D020022:Genetic Predisposition to Disease / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics; D016350:Leucine Zippers / Q000235:genetics*; D008297:Male; D051379:Mice; D064547:Myxovirus Resistance Proteins; D017686:Oncorhynchus mykiss / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis*; D012209:Rhabdoviridae; D018353:Rhabdoviridae Infections / Q000235:genetics / Q000662:veterinary*
chemical_list: D000998:Antiviral Agents; C579070:Mx1 protein, mouse; D064547:Myxovirus Resistance Proteins; D011506:Proteins; D012333:RNA, Messenger; D019204:GTP-Binding Proteins