Miyata H, Tsunoda H, Kazi A, Yamada A, Khan M A, Murakami J, Kamahora T, Shiraki K, Hino S
Departments of Virology, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan.
J Virol. 1999 May;73(5):3582-6. doi: 10.1128/JVI.73.5.3582-3586.1999.
The sequence data (H. Okamoto et al., Hepatol. Res. 10:1-16, 1998) of a newly discovered single-stranded DNA virus, TT virus (TTV), showed that it did not have the terminal structure typical of a parvovirus. Elucidation of the complete genome structure was necessary to understand the nature of TTV. We obtained a 1.0-kb amplified product from serum samples of four TTV carriers by an inverted, nested long PCR targeted for nucleotides (nt) 3025 to 3739 and 1 to 216 of TTV. The sequence of a clone obtained from serum sample TA278 was compared with those registered in GenBank. The complete circular TTV genome contained a novel sequence of 113 nt (nt 3740 to 3852 [=0]) in between the known 3'- and 5'-end arms, forming a 117-nt GC-rich stretch (GC content, 90.6% at nt 3736 to 3852). We found a 36-nt stretch (nt 3816 to 3851) with an 80.6% similarity to chicken anemia virus (CAV) (nt 2237 to 2272 of M55918), a vertebrate circovirus. A putative SP-1 site was located at nt 3834 to 3839, followed by a TATA box at nt 85 to 90, the first initiation codon of a putative VP2 at nt 107 to 109, the termination codon of a putative VP1 at nt 2899 to 2901, and a poly(A) signal at nt 3073 to 3078. The arrangement was similar to that of CAV. Furthermore, several AP-2 and ATF/CREB binding sites and an NF-kappaB site were arranged around the GC-rich region in both TTV and CAV. The data suggested that TTV is circular and similar to CAV in its genomic organization, implying that TTV is the first human circovirus.
新发现的单链DNA病毒TT病毒（TTV）的序列数据（H. Okamoto等人，《肝脏病学研究》10:1 - 16，1998年）表明，它不具有细小病毒典型的末端结构。阐明完整的基因组结构对于了解TTV的本质至关重要。我们通过针对TTV核苷酸（nt）3025至3739以及1至216的反向巢式长PCR，从四名TTV携带者的血清样本中获得了一个1.0 kb的扩增产物。将从血清样本TA278获得的一个克隆的序列与GenBank中登记的序列进行比较。完整的环状TTV基因组在已知的3'和5'末端臂之间包含一个113 nt的新序列（nt 3740至3852 [=0]），形成了一个117 nt富含GC的片段（在nt 3736至3852处GC含量为90.6%）。我们发现一个36 nt的片段（nt 3816至3851）与鸡贫血病毒（CAV）（M55918的nt 2237至2272）有80.6%的相似性，CAV是一种脊椎动物圆环病毒。一个假定的SP - 1位点位于nt 3834至3839，随后是一个位于nt 85至90的TATA框，假定的VP2的第一个起始密码子位于nt 107至109，假定的VP1的终止密码子位于nt 2899至2901，以及一个位于nt 3073至3078的多聚腺苷酸信号。这种排列与CAV的相似。此外，在TTV和CAV的富含GC区域周围都排列着几个AP - 2和ATF/CREB结合位点以及一个NF - κB位点。数据表明TTV是环状的，并且在基因组组织上与CAV相似，这意味着TTV是第一种人类圆环病毒。
