Abstract
Avian leukosis virus (ALV) is an oncogenic virus causing a variety of neoplasms in chickens. The group of avian leukosis virus in chickens contains six closely related subgroups, A to E and J. The prevalence of ALVs in hosts may have imposed strong selective pressure toward resistance to ALVs infection. The tvb gene encodes Tvb receptor and determines susceptibility or resistance to the subgroups B, D, and E ALV. In this study, we characterized a novel resistant allele of the tvb receptor gene, tvb(r3), which carries a single-nucleotide substitution (c.298C>T) that constitutes a premature termination codon within the fourth exon and leads to the production of a truncated Tvb(R3) receptor protein. As a result, we observed decreased susceptibility to infection by ALV-B, ALV-D and ALV-E both in vitro and in vivo, and decreased the binding affinity of the Tvb(R3) receptor for the subgroups B, D, and E ALV envelope glycoproteins. Additionally, we found that the tvb(r3) allele was prevalent in Chinese broiler lines. This study demonstrated that premature termination codon in the tvb receptor gene can confer genetic resistance to subgroups B, D, and E ALV in the host, and indicates that tvb(r3) could potentially serve as a resistant target against ALV-B, ALV-D and ALV-E infection.