Molecular characterization, expression analysis and association study with immune traits of porcine PSMB6 gene

PSMB6 subunit belongs to the 20S proteasomal subunit family, which plays an importance role in the antigen presentation by MHC class I molecular. The full-length genomic DNA sequence was obtained by PCR and the full-length CDS of porcine PSMB6 was isolated by the reverse transcriptase-polymerase chain reaction (RT-PCR). The deduced protein of 239 amino acids showed 86% identity to the corresponding human sequence. RT-PCR revealed that porcine PSMB6 gene was expressed in seven tissues studied (heart, liver, spleen, lung, kidney, skeletal muscle and fat) and SYBR Green real-time RT-PCR analysis showed PSMB6 gene was expressed highest in spleen. A single nucleotide substitution resulting in the amino acid change (19Pro-19His) was detected within exon 1 and other two single nucleotide polymorphisms were detected in intron 1. The Genetic variations were identified in eight pig breeds showed diverse results. Furthermore, we found that the single nucleotide polymorphisms (SNP, G/T300) was significantly associated with delayed type hypersensitivity (DTH, P < 0.05), immunoglobin G (IgG1, P < 0.05), white blood cell count (WBC, P < 0.05). Using the pig/rodent somatic cell hybrid panel (SCHP), we mapped the porcine PSMB6 gene to SSC12, in agreement with comparative mapping data.