Phylogenetic Analysis of Porcine Endogenous Retroviruses Expressed in Chinese Pigs Based on Envelope Sequences

The promise of successful clinical xenotransplantation is now offset by the potential risk of transmission of porcine endogenous retrovirus (PERV). PERV consists of three subtypes according to the varieties of env sequences. We analyzed PERV subtypes in two species of Chinese pigs (Banna minipig inbred, BMI, and Wu-Zhi-Shan pig, WZSP). Positive A and B were detected while positive C was absent in the analyzed Chinese pigs. The polymerase chain reaction products were then cloned into a pGEM-T vector system and sequenced. Phylogenetic trees were constructed from the translated amino acids of PERVs and other type C and type D retrovirus, as well as the lentivirus in the GeneBank. The results suggested that PERV-A and PERV-B that exist in Chinese pig genomes share similarities with other PERV from the GeneBank and some type C retroviruses, including lymphotropic, leukemic and endogenous retroviruses.