Construction of an infectious clone of simian foamy virus of Japanese macaque (SFVjm) and phylogenetic analyses of SFVjm isolates

Foamy viruses belong to the genus Spumavirus of the family Retroviridae and have been isolated from many mammalian species. It was reported that simian foamy viruses (SFVs) have co-evolved with host species. In this study, we isolated four strains (WK1, WK2, AR1 and AR2) of SFV (named SFVjm) from Japanese macaques (Macaca fuscata) in main island Honshu of Japan. We constructed an infectious molecular clone of SFVjm strain WK1, termed pJM356. The virus derived from the clone replicated and induced syncytia in human (human embryonic kidney 293T cells), African green monkey (Vero cells) and mouse cell lines (Mus dunni tail fibroblast cells). Phylogenetic analysis also revealed that these four SFVjm strains formed two distinct SFVjm clusters. SFVjm strains WK1 and WK2 and SFV isolated from Taiwanese macaques (Macaca cyclopis) formed one cluster, whereas strains AR1 and AR2 formed the other cluster with SFV isolated from a rhesus macaque (Macaca mulatta).