title: Genetic and phylogenetic analyses of human T-cell lymphotropic virus type I variants from Melanesians with and without spastic myelopathy.
abstract: Molecular variants of human T-cell lymphotropic virus type I (HTLV-I) have been isolated recently from lifelong residents of remote Melanesian populations, including a Solomon Islander with tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM) or HTLV-I myeloneuropathy. To clarify the genetic heterogeneity and molecular epidemiology of disease-associated strains of HTLV-I, we enzymatically amplified, then directly sequenced representative regions of the gag, pol, env, and pX genes of HTLV-I strains from Melanesians with and without TSP/HAM, and aligned and compared these sequences with those of HTLV-I strains from patients with TSP/HAM or adult T-cell leukemia/lymphoma and from asymptomatic carriers from widely separated and culturally disparate populations. Overall, the HTLV-I variant from the Solomon Islander with TSP/HAM, like HTLV-I strains from asymptomatically infected Melanesians, diverged by approx 7% from cosmopolitan HTLV-I strain. No disease-specific viral sequences were found. Gene phylogenies, as determined by the unweighted pair-group method of assortment and by the maximum parsimony method, indicated that the Melanesian and cosmopolitan strains of HTLV-I have evolved along separate geographically dependent lineages, one comprised of HTLV-I strains from Papua New Guinea and the Solomon Islands, and the other composed of virus strains from Japan, India, the Caribbean, Polynesia, the Americas, and Africa. The total absence of nonhuman primates in Papua New Guinea and the Solomon Islands precludes any possibility that the Melanesian HTLV-I strains have evolved recently from the simian homolog of HTLV-I.
authors.affiliation: Laboratory of Central Nervous System Studies, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
authors.forename: V R
authors.initials: VR
authors.lastname: Nerurkar
authors.forename: K J
authors.initials: KJ
authors.lastname: Song
authors.forename: R R
authors.initials: RR
authors.lastname: Melland
authors.forename: R
authors.initials: R
authors.lastname: Yanagihara
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D015752:Genes, env; D015750:Genes, gag; D016355:Genes, pX; D015751:Genes, pol; D014644:Genetic Variation; D015368:Human T-lymphotropic virus 1 / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008542:Melanesia; D008875:Middle Aged; D008969:Molecular Sequence Data; D010219:Papua New Guinea; D015493:Paraparesis, Tropical Spastic / Q000821:virology*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013601:T-Lymphocytes; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D017931:DNA Primers; D014759:Viral Envelope Proteins