The porcine endogenous retrovirus long terminal repeat contains a single nucleotide polymorphism that confers distinct differences in estrogen receptor binding affinity between PERV A and PERV B/C subtypes

Porcine endogenous retroviruses (PERV) have been shown to have zoonotic pot ential, both in vitro and in vivo. Once integrated into the host cell genom e activation of the proviral genes is ultimately dependent upon transactiva tion of the long terminal repeat (LTR). Currently there is no direct eviden ce of host cell transcription factors interacting with PERV LTRs. Using com parative genomics we discovered a potentially functional single nucleotide polymorphism (SNP) within the U5 region downstream of the TATA box in the P ERV LTR that distinguishes PERV A from PERV a and PERV C subtypes. We demon strated that the SNP occurs within a potential hormone-responsive region wh ere it has a profound effect, not only upon estrogen receptor binding but a lso upon the binding of other transcription factors at this site. These res ults suggest that differences in transcriptional regulation between PERV su btypes are subtle and, as for other retroviruses, transcription can be medi ated by steroid hormone receptors. (C) 2001 Academic Press.