Investigation of Porcine Endogenous Retrovirus (PERV) Loci in the Genome of Vietnamese Domestic Pigs

Xenotransplantation of pig organs to human has been hoped to make up the shortage of life-saving organ transplants. However, pig genome is riddled with many copies of porcine endogenous retrovirus (PERV) which may cause a potential risk of producing infectious viral particles in the recipient. There has been a few studies examined copy number of PERVs suggesting that Asian pigs might have less copies of PERV than those of Western breeds. Therefore we aimed to survey PERVs in the genome of domestic pigs in Vietnam, where a mine of scarce genetic resource of livestock species resides. Fifteen domestic breeds of pigs from far and wide areas of the country were used to obtain genomic DNA samples. Detection of PERV copy in the genome was conducted by PCR using primers targeted to amplify pol and env genes in PERV-A, B and C. We elucidated that PCR amplification of pol in PERV-A, B and C was faint in 2 of 15 pig breeds. Interestingly, PCR amplification of env in PERV-A and B was very faint in 6 of 15 breeds. Furthermore, no amplification of env in PERV-C was observed in all breeds examined. Our results suggested that several domestic pig breeds in Vietnam might have few copy of infectious PERB-A and B. However, since we only applied PCR to detect PERV genes, we still need to consider investigating how many copies indeed exist in the genome of the particular pig breeds identified to be potentially low copy of PERV.