ThetaxGene Sequences Form Two Divergent Monophyletic Lineages Corresponding to Types I and II of Simian and Human T-Cell Leukemia/Lymphotropic Viruses

Abstract

Evolutionary associations of human and simian T-cell leukemia/lymphotropic viruses I and II (HTLV-I/II and STLV-I/II) are inferred from phylogenetic analysis of tax gene sequences. Samples studied consisted of a geographically diverse assemblage of viral strains obtained from 10 human subjects and 20 individuals representing 12 species of nonhuman primates. Sequence analyses identified distinct substitutions, which distinguished between viral types I and II, irrespective of host species. Phylogenetic reconstruction of nucleotide sequences strongly supported two major evolutionary groups corresponding to viral types I and II. With the type I lineage, clusters were composed of strains from multiple host species. A genetically diverse, monophyletic lineage consisting of eight new viral strains from several species of Asian macaques was identified. The second lineage consisted of a monophyletic assemblage of HTLV-II/STLV-II strains from Africa and the New World, including an isolate from a pygmy chimp (Pan paniscus) as an early divergence within the lineage. High levels of genetic variation among strains from Asian STLV-I macaque suggest the virus arose in Asia. Evidence of the origin of the type II virus is less clear, but diversity among HTLV-II variants from a single isolated population of Mbati villagers is suggestive but not proof of an African origin.

Genetic diversity and population structure of rice stripe virus in China

“…If a viral population shows higher genetic diversity, it is normally considered more ancient Fargette et al, 2006;Gessain et al, 1992;Giri et al, 1997;Koralnik et al, 1994;Moya & Garcia-Arenal, 1995). The historical record of disease may or may not be consistent with the extent of genetic diversity.…”

Cellular Immune Responses against Simian T-Lymphotropic Virus Type 1 Target Tax in Infected Baboons

“…Simian T-lymphotropic virus type 1 (STLV-1) is closely related to HTLV-1 and infects several nonhuman primate species. Phylogenetic analysis of the conserved tax gene sequences indicates that STLV-1 and HTLV-1 are evolutionarily related (32). Furthermore, STLV-1 Tax and STLV-1 bZIP factor (SBZ) have functions similar to those of their equivalents from HTLV-1 (19,33).…”

Characterization of a simian T-lymphotropic virus from a wild-caught orang-utan (Pongo pygmaeus) from Kalimantan, Indonesia.

“…3). Clearly STLV OU-KA falls within the HTLV-I\STLV-I evolutionary cluster as described by Giri et al (1997) but constitutes an isolated member of the subcluster consisting of Asian STLV-I strains from India, Japan and Indonesia.…”

“…Phylogenetic analyses of STLV and HTLV isolates have suggested that HTLV-II is genetically distinct and separated from a common ancestor virus before HTLV-I evolved from STLV during multiple interspecies transmissions (Koralnik et al, 1994 ;Saksena et al, 1994 ;Song et al, 1994). Also, there are indications for an Asian origin of the HTLV\STLV viruses (Song et al, 1994 ;Giri et al, 1997). For the great apes, chimpanzee, gorilla and orang-utan, STLVs have been characterized from the common chimpanzee (Pan troglodytes) (Koralnik et al, 1994) and the pygmy chimpanzee (P. paniscus) (Giri et al, 1994 ;Vandamme et al, 1996), while antibodies cross-reacting with STLV have been described in gorillas (Gorilla gorilla) (Ibrahim et al, 1995).…”

“…The high similarity between strains from different HTLV-I clades (ATK and MEL5) and from STLV strains originating from the same geographical region but isolated from other species is not surprising as tax\rex is the most conserved region among STLVs, HTLV-I and HTLV-II (Sherman et al, 1992 ;Shaw et al, 1984). The strong conservation of the tax\rex region makes it particularly suitable for determination of phylogenetic relationships between HTLVs and STLVs (Giri et al, 1997). The short 118 bp tax\rex fragment from the diagnostic PCR was used to construct a phylogenetic tree using the neighbour-joining method as implemented in the MEGA package (Kumar et al, 1993) (Fig.…”