Using CRISPR/Cas9 for generation the cd209 knockout is a way to get cattle breeds resistant to the Bovine leukemia virus (BLV)

Abstract

Bovine leukemia virus (BLV) causes enzootic leukemia - a chronic infectious disease occurring against the background of embedding the virus in the genome of B-lymphocytes and leading to malignization, invasion of tumor cells in organs and the formation of tumors. The disease is common in the United States, Japan, and Asia. In Russia, up to 30% is infected with BLV. Moreover, there is evidence of the presence of antibodies to the BLV virus in some groups of people, and the relationship between BLV and cancer in humans is widely discussed. All this indicates an urgent need to study BLV and create breeds resistant to it. The development of approaches to solving this problem is complicated by the fact that the receptor through which the infection is carried out is still unknown. Recently, it has been suggested that the virus penetrates the animal's lymphocytes using the CD209 molecule. In this paper, we propose a genome editing system based on CRISPR/Cas9 to get a knockout for this gene. We assume that animals obtained using the presented genome editing system will be resistant to infection with the bovine leukemia virus.

Phenotypic Selection of Dairy Cattle Infected with Bovine Leukemia Virus Demonstrates Immunogenetic Resilience through NGS-Based Genotyping of BoLA MHC Class II Genes

“…Likewise, cells with overexpressed CAT1 levels became susceptible to BLV infection [43]. In addition to CAT1/SLC7A1, there is evidence that identifies the CD209 protein as a potential receptor for BLV [44,45]. CD209 is expressed in B-cells [45] and polymorphisms in its promoter has been linked to HTLV [46].…”

“…CD209 is expressed in B-cells [45] and polymorphisms in its promoter has been linked to HTLV [46]. More recently, a method has been developed to out the CD209 protein in hopes of creating cells that display resistance to BLV [44]. Although a definitive BLV receptor has not been identified in vivo, these two examples further suggest the influence of genetic regions outside aside from BoLA genes that influence BLV phenotype.…”

An Outlook on Global Regulatory Landscape for Genome-Edited Crops

“…Off-target mutations in human cancer cells have been attributed to sgRNA mismatching of dysfunctional repair mechanisms [ 173 ]. Similar off-targets have been observed in farm animals, including pigs and cattle [ 174 , 175 ], and non-specific editing has been detected in genome-edited mice [ 176 ]. Other studies have shown low or no detectable off-targets in genome-edited animals, possibly because it can be difficult to distinguish between off-targets and natural variations.…”

Improvement of the technique for the bovine genome editing using the example of knockout of the CD 209 receptor responsible to the bovine leukemia virus

“…Thus, this method was technically very difficult due to the inability to visualize pronuclei. In addition, it also had zero efficiency in case of editing the Cd209 gene [15]. The method of viral vectors had relatively low efficiency and undesirable side effects.…”