Molecular characterization and phylogenetic relationship of HERV-W family in the Macaca fuscata

A human endogenous retrovirus, HERV-W, has recently been identified on human chromosome 7 and contains a single complete open reading frame putatively encoding an envelope protein. Its env gene was expressed in various tissues, and mainly in human placenta. We investigated env gene of the HERV-W family in the Macaca fuscata (Japanese monkey). The env gene expression was detected in various tissues (testis, prostate, kidney, cerebellum, thymus, placenta, intestine, stomach, ovary) of the Japanese monkey by RT-PCR. Southern blot analysis indicated that the monkey genome contained at least 15 copies of the HERV-W family. Using the PCR approach with the monkey genome, thirteen env fragments of the HERV-W family were identified and analyzed. These env fragments from monkey showed a high degree of sequence similarity (91-94%) to that of human HERV-W (AF072506). Putative amino acid sequences of the env fragments indicated multiple frameshifts and termination codons by deletion/insertion or point mutation in all clones identified in this study. Phylogenetic analysis of the env fragments derived from the monkey genome with those of the human genome showed a random sister relationship.