UC Davis

In this study, we report the generation of CD209 gene knockout sheep, utilizing electroporation-mediated CRISPR-Cas9 genome editing, as a model to test whether this might make cattle resistance against Bovine Leukemia Virus (BLV). This approach exploits the CD209 gene's role as a receptor for BLV, hypothesizing that its knockout would confer resistance to infection. Our methodology involves specific guide RNAs targeting the sheep CD209 gene, followed by electroporation into ovine zygotes to induce targeted gene disruptions. It was hypothesized that a gene knockout of CD209 would result in the inability of the virus to bind and enter the cell; therefore, creating disease resistance. The resultant lambs exhibited varied mosaicism and phenotypic outcomes associated with the gene edit, indicative of the CRISPR-Cas9 system's effectiveness and efficiency. This study not only demonstrates a novel application of gene editing in livestock but also underlines the potential of sheep as surrogate models in BLV research, due to their analogous immunological responses and shorter gestational periods compared to cattle. The successful application of this technology paves the way for future research in genetic engineering for livestock disease resistance, with significant implications for animal health management and agricultural productivity.