Sequential disruption of ALV host receptor genes reveals no sharing of receptors between ALV subgroups A, B, and J

BACKGROUND: Previously, we showed that targeted disruption of viral receptor genes in avian leukosis virus (ALV) subgroups using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9))-based genome editing confers resistance to ALV subgroups B and J. Here, we used the same strategy to target the receptor expressed by ALV subgroup A (TVA) and generate chicken cells resistant to infection by this virus. RESULTS: CRISPR/Cas9-based disruption of exon 2 within the tva gene of DF-1 fibroblasts conferred resistance to infection by ALV subgroup A regardless of whether frameshift mutations were introduced during editing. Conversely, overexpression of the wild-type TVA receptor (wtTVA) by tva-modified DF-1 clones restored susceptibility to ALV subgroup A. The results confirm that exon 2, which contains the low-density lipoprotein receptor class A domain of TVA, is critical for virus entry. Furthermore, we sequentially modified DF-1 cells by editing the tva, tvb, and Na(+)/H(+) exchange 1 (chNHE1) genes, which are the specific receptors for ALV subgroups A, B, and J, respectively. CONCLUSIONS: Simultaneous editing of multiple receptors to block infection by different subgroups of ALV confirmed that ALV subgroups A, B, and J do not share host receptors. This strategy could be used to generate cells resistant to multiple viral pathogens that use distinct receptors for cell entry. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s40104-019-0333-x) contains supplementary material, which is available to authorized users.