Genomes and Proteins of HTLV-I and -II and Their Function

Abstract

The genomes and proteins of HTLV-I and HTLV-II are shown in Fig. 4. The genomes consist of high-molecular weight polyadenylated RNA. Molecular hybridization experiments with complementary DNA (cDNA) prepared by in vitro reverse transcription of the viral RNA by its endogenous reverse transcriptase have shown that HTLV-I is not closely related to any of the previously known animal retroviruses (Reitz et al. 1981). These studies also showed that the viral genome was only present in the tumor cell genome, but not in the genome of normal cells of an infected patient (Gallo et al. 1982). This indicated that HTLV-I was an exogenous retrovirus acquired by horizontal infection. The molecular cloning and complete sequencing of HTLV-I was first achieved by Yoshida’s group in Japan (Seiki et al. 1983). This, and other cloning and sequencing work (Manzari et al. 1983; Gelmann et al. 1984) allowed detailed molecular studies of the genome structure, its functions, and site of integration.