[Cloning and sequencing of a Chinese complete TTV gene].
OBJECTIVE
To obtain the complete TT virus gene from a Chinese isolate.


METHODS
Long-PCR was performed for amplifying the TTV gene from the serum of a Chinese with non-A to non-G hepatitis. Three overlapped DNA fragments were obtained, which contained 199 bp (1-199), 3 269 bp (38 approximately 3 306) and 434 bp (3 306 approximately 3 739) separately. These PCR products were sequenced by the standard method.


RESULTS
The complete TTV gene (named as TTV CHN1) consisting of 3 739 nucleotides contained two ORFs. The first ORF located at 589 approximately 2 901 nt, coding 770 amino acids; the second located at 107 approximately 715 nt, coding 202 amino acids. In this genome, G is 22.25%, C 25.54%, A 31.26% and T 20.97%. The homology of Chinese and Japanese TTV genes was more than 94% at both nucleotide and amino acid levels. There exists a hyper-variation region (HVR) spanning at 1 380 approximately 1 800 bp. In this region, the HVR homology of Chinese and Japanese TTV genes was 88% and 81% at nucleotide and amino acid levels, respectively.


CONCLUSIONS
Chinese and Japanese TTV isolates belong to the same genotype. There exists a hyper-variation region (HVR) spanning at 1 380 approximately 1 800 bp.
Zhou
Y
Y
Beijing Institute of Microbiology and Epidemiology, China Academy of Medical Sciences, Beijing 100071, China.
Dong
J
J
He
Z
Z
D000595:Amino Acid Sequence; D001483:Base Sequence; D002681:China; D003001:Cloning, Molecular; D004279:DNA, Viral; D005814:Genes, Viral; D006801:Humans; D007564:Japan; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D012689:Sequence Homology, Nucleic Acid; D022783:Torque teno virus / Q000235:genetics* / Q000302:isolation & purification
D004279:DNA, Viral