Structural profile and diversity of immunoglobulin genes in the Arctic Fox.

Abstract

Immunoglobulins are important components of humoral immunity and play a crucial role in protecting the body from external antigens. The Arctic fox is an important member of furbearer farming, but due to the lack of research on the immune system of the Arctic fox, animal welfare regarding Arctic fox farming has still not received enough attention. In this study, we used the Arctic fox as a research subject, described the gene locus structure of the Arctic fox immunoglobulin germline by genome comparison, and analysed the mechanism of expression diversity of the antibody pool of the Arctic fox by rapid amplification of cDNA 5' ends and high-throughput sequencing. The results showed that the Arctic fox IgH, Igκ and Igλ loci were located on chromosome 6, chromosome 5 and chromosome 14, respectively. The number of variable (V) genes identified were 18, 11 and 10, and the number of joining (J) were 3, 4 and 13 and six diversity (D) genes in the heavy chain, respectively. Among them, the D genes, J genes and constant region genes of the heavy chain were arranged in the middle of the two variable heavy gene clusters; Arctic fox had a strong preference for the use of V genes, D genes and J genes, which resulted in a low level of V(D)J recombination diversity; linkage diversity analyses showed that random deletion of the V and J genes and insertion of the N and P nucleotides of the immunoglobulins of the Arctic foxes had a large impact on the linkage diversity of the IgH, whereas the light chain The linkage diversity was mainly contributed by the random deletion of V and J genes, and the insertion of N and P nucleotides had a smaller effect; somatic hypermutation (SHM) analysis showed that the mutation types of SHM of the heavy and light chains of the Arctic fox had a strong bias towards G>A and A>G, and the bias exhibited by the three chains was basically the same. By analysing the structure and expression diversity analysis of the Arctic fox gene loci, this study could provide a theoretical basis for antibody design and vaccine development in the Arctic fox, and provide new insights to further improve the animal welfare level of Arctic fox farming.