Structure and polymorphisms of the 5' regulatory region of porcine adenylate kinase 3-like 1 gene and effect on trait of meat quality

The porcine adenylate kinase 3-like 1 (AK3L1) gene is considered as a potential candidate gene among the encoded isoforms of adenylate kinase for meat quality based on the functional role of the AK3L1 gene in energy metabolism via high-energy phosphoryl transfer reaction. The genomic position of the AK3L1 gene is located in the QTL region, which codes for traits of meat quality. We characterized the genomic structure of the porcine AK3L1 gene and found polymorphisms in the 5' regulatory region. Typical transcription factor binding sites, such as the TATA box and initiator sequence, were not found. However, the AK3L1 gene had two different transcription start points with different transcripts from Exon 1a and 1b isoforms within the high G+C content region without changing the translation initiation site. The SNPs around two alternative transcription start points in the porcine AK3L1 gene were significantly associated with the following traits of meat quality: back fat thickness (SNP1, P < 0.01), IMF (SNP5, P < 0.06), muscle pH (SNP4, P < 0.05), meat color (SNP1, P < 0.03), and drip loss (SNP1, 2, 4, and 5, P < 0.04). We suggest that SNPs of the AK3L1 gene can induce variation in meat formation and may be potential markers for the quality of pig meat.