title: Human T cell lymphotropic virus type I (HTLV-I) p12I is dispensable for HTLV-I transmission and maintenance of infection in vivo.
abstract: The function of the p12(I) protein of human T cell lymphotropic virus type I (HTLV-I) has been under debate. p12K (lysine) and p12R (arginine) variants of this protein at amino acid 88 and a shorter life of p12K had been reported by another group. Because HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients usually have a higher provirus load than asymptomatic HTLV-I carriers (ACs), and p12(I) had been suggested to confer a proliferative effect on HTLV-I-infected cells in vitro, it is possible that the relatively unstable p12K is less frequent in HAM/TSP patients than in ACs. To elucidate whether p12K and other alterations in the p12 gene were related to the outcome of HTLV-I infection, we sequenced the p12 gene in 144 HAM/TSP patients, 41 adult T cell leukemia (ATL) patients, and in 46 ACs. p12K was observed in only two HAM/TSP patients, but was not present in either ATL patients or ACs. Interestingly, a premature termination codon in the p12 was observed in 5.6% of HAM/TSP patients and in 4.9% of ATL patients but none was found in ACs. The p12 initiation codon was destroyed in one HAM/TSP patient. These HTLV-I variants with truncated p12 protein or with a destroyed initiation codon in the p12 gene appeared to have been transmitted in the subjects' families. These findings suggest that p12 is dispensable for the transmission and maintenance of HTLV-I infection, although it is premature to conclude that sequence varitation in the p12 gene is associated with differences in the outcome of HTLV-I infection.
authors.affiliation: Division of Blood Transfusion Medicine and Cell Therapy, Kagoshima University Hospital, Kagoshima 890-8520, Japan. furukawy@m2.kufm.kagoshima-u.ac.jp
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Furukawa
authors.forename: Koichiro
authors.initials: K
authors.lastname: Usuku
authors.forename: Shuji
authors.initials: S
authors.lastname: Izumo
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Osame
mesh_terms: D000328:Adult; D005260:Female; D016356:Gene Products, tax / Q000235:genetics; D016355:Genes, pX / Q000235:genetics; D014644:Genetic Variation; D015490:HTLV-I Infections / Q000235:genetics / Q000503:physiopathology* / Q000635:transmission* / Q000821:virology; D015368:Human T-lymphotropic virus 1 / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015493:Paraparesis, Tropical Spastic / Q000235:genetics / Q000503:physiopathology / Q000635:transmission / Q000821:virology; D012150:Polymorphism, Restriction Fragment Length; D011533:Proviruses; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D019562:Viral Load; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D016356:Gene Products, tax; D009856:Oncogene Proteins, Viral; D014157:Transcription Factors; D054334:Viral Regulatory and Accessory Proteins; C084305:p12I protein, Human T-lymphotropic virus 1