HTLV-1a tax gene and long terminal repeat sequences from Argentinean strains reveal disagreement with tax restriction fragment length polymorphism subtyping.
Sequence and cluster analysis have shown two HTLV-1a tax gene subgroups, tax A and tax B, which are related to long terminal repeat (LTR) molecular subtypes. On the basis of subgroup-specific nucleotide substitutions, restriction fragment length polymorphism (RFLP) analysis of the tax gene for subtyping HTLV-1a isolates was proposed. In this study we genetically characterized the tax gene from 63 HTLV-1-positive Argentinean individuals, including 14 patients with HTLV-1-associated myelopathy/tropical spastic paraparesis and 49 healthy HTLV-1 carriers. RFLP analysis showed that 48 samples yielded the tax A profile (76.19%) and that 15 samples contained the uncut tax B profile (23.81%). However, the LTR and tax sequence analysis revealed that in fact only 2 from the 15 samples belonged to the HTLV-1aB subgroup, presenting four tax B subgroup-specific nucleotide substitutions. The tax gene cluster analysis also confirmed that the majority of Argentinean strains belonged to the Transcontinental HTLV-1aA subgroup. These results indicate that the tax gene RFLP assay which has been proposed and used by some authors to screen HTLV-1a subgroups, is not a suitable tool to perform molecular epidemiological characterization of HTLV-1a populations.
Iñiguez
Alena M
AM
Departamento de Genética, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. alena@ioc.fiocruz.br
Otsuki
Koko
K
Gastaldello
Rene
R
Gallego
Sandra
S
Vicente
Ana Carolina P
AC
D001118:Argentina; D016356:Gene Products, tax / Q000737:chemistry / Q000235:genetics*; D016355:Genes, pX / Q000235:genetics; D015490:HTLV-I Infections / Q000821:virology; D015368:Human T-lymphotropic virus 1 / Q000145:classification* / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D015493:Paraparesis, Tropical Spastic / Q000821:virology; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D020079:Terminal Repeat Sequences / Q000235:genetics*
D016356:Gene Products, tax; C514970:tax protein, Human T-lymphotrophic virus 1