ENVELOPE GENE-SEQUENCES OF HUMAN T-LYMPHOTROPIC VIRUS TYPE-I IN TAIWAN

Three major types of HTLV-I had been proposed, the Melanesian type, th e Zairian type, and the cosmopolitan type, which was further divided i nto subtypes A, B and C, according to the phylogenetic tree constructe d from LTR sequences of current HLTV-I isolates. In this study, the en velope gene sequences of HTLV-I from 9 Taiwanese were analyzed. Based on the phylogenetic tree constructed by unweighed pair group method an d the sequence homology analysis by GCG computer programs, the envelop e gene sequences of HTLV-I proviruses from these 9 Taiwanese belonged to subtype A or subtype B of the cosmopolitan type and were closely re lated to HTLV-I from Japan. Twelve subtype-specific nucleotide variati ons were deduced from the comparison of complete or partial envelope g ene sequences of 16 HTLV-I isolates of known subtypes as well as those of 9 Taiwanese. These data provided the basis for subtyping the cosmo politan type of HTLV-I by amplification of envelope gene sequences and restriction fragment length polymorphism studies. A more extensive su rvey based upon this proposal was warranted.