Expression and SNP association analysis of porcine FBXL4 gene

As a kind of E3 ligase, the product of FBXL4 gene belongs to a member of FBLs which is the biggest eukaryotic subfamily of F-BOX proteins, it can recognize some substrate through particular protein–protein interaction domains. To investigate its functions, the polymorphism and association analysis was analyzed. The partial cDNA of porcine FBXL4 with 2384 bp long was first cloned; the deduced protein comprises a conserved F-BOX domain at position from the 277th to 332nd amino acid. The phylogenetic tree indicated porcine FBXL4 has the closest genetic relationship with bovine FBXL4 than other selected animal species. Ten tissue expression level of porcine FBXL4 mRNA fluctuated remarkably in a large range by quantitative RT-PCR analysis. For two identified SNPs, the genotyping analysis of Tail showed TT genotype owned dominance in introduced Landrace pig and miniature Guizhou and Wuzhishan breeds, but CC genotype was more than two other genotypes in miniature Laiwu breed. While in another genotyping analysis of BsaJI, CC genotype was obviously more than other genotypes in two kinds of Chinese miniature pig breeds and introduced Landrace pig breeds. Furthermore, the association analysis with immune traits and blood parameters revealed that SNP Tail was significantly associated with the lymphocyte percentage (P = 0.0166) and the antibody levels for pseudorabies virus vaccination (P = 0.0001) of neonate piglets at 0 day. Meanwhile, SNP BsaJI was significantly associated with lymphocyte percentage of individuals at 32 days (P = 0.0351), neutrophil percentage (P = 0.0005), the absolute lymphocyte count (P = 0.0458), and the mixed cells (P = 0.0010) of neonate piglets at 0 day.