Gene expression of vascular endothelial growth factor A and hypoxic adaptation in Tibetan pig

Bo Zhang, Yangzong Qiangba, Peng Shang, Yunfeng Lu, Yuzeng Yang, Zhixiu Wang, Hao Zhang

Vascular endothelial growth factor A (VEGFA) can induce endothelial cell proliferation, promote cell migration, and inhibit apoptosis. These processes play key roles in physiological blood vessel formation and pathological angiogenesis. In this study, we examined VEGFA gene expression in the heart, liver, and kidney of Tibetan pigs (TP), Yorkshire pigs that migrated to high altitudes (YH), and Yorkshire pigs that lived at low altitudes (YL). We used PCR and Sanger sequencing to screen for single nucleotide polymorphisms (SNPs) in 5'-flanking DNA and exons of the VEGFA gene. Quantitative real-time PCR and western blots were used to measure expression levels and PCR products were sequenced. Results showed that the VEGFA mRNA and protein expression in heart, liver and kidney of TP was higher than that in YH and YL. In addition, the mRNA sequence of the pig VEGFA gene was conserved among pig breeds, and only five SNPs were found in the 5'-flanking region of the VEGFA gene, the allele frequency distributions of the 5 SNPs were not significantly different between the TP, Yorkshire (YL), and Diannan small-ear (DN) pig populations. In conclusion, the Tibetan pig showed high levels of VEGFA gene expression in several hypoxic tissues, which suggests that the VEGFA gene may play a major functional role in hypoxic adaptation.