Arch Virol (2000) 145: 1543–1559
The entire nucleotide sequences of two distinct TT virus (TTV)
isolates (TJN01 and TJN02) remotely related to the original
, H. Okamoto
, T. Nishizawa
, A. Tawara
, M. Takahashi
, Y. Miyakawa
, and M. Mayumi
Immunology Division and Division of Molecular Virology,
Jichi Medical School, Tochigi-Ken, Japan
First Department of Internal Medicine, Yamanashi Medical University,
Japanese Red Cross Saitama Blood Center, Saitama-Ken, Japan
Miyakawa Memorial Research Foundation, Tokyo, Japan
Accepted March 22, 2000
Summary. TT virus (TTV) has a wide range of sequence divergence by which
it is classiﬁed into at least 16 genotypes. A TTV isolate of genotype 12 (TJN01)
and another of genotype 13 (TJN02) were sequenced in the entire genome, and
compared with the reported TTV isolates. TJN01 and TJN02 had genomic lengths
of3787and3794 nucleotides(nt), respectively,which wereshorter by66 and59 nt
than the prototype TTV isolate of genotype 1 (TA278). TJN01 and TJN02 shared
the nucleotide sequence with TA278 merely in 53.9% and 55.2%, respectively.
They possessed two major open reading frames (ORFs) and the noncoding region
with a GC-rich region forming stem-loop structures, which are characteristic
of TTV. However, their amino acid sequences in ORF1 were similar to that of
TA278 in only 35.4 and 34.0%, respectively; TJN01 was 45.4% similar to TJN02.
Comparison with TTV isolates of the same genotype identiﬁed hypervariable
regions in ORF1 of TJN01 and TJN02, as in the prototype TTV of genotype 1.
However, quasispecies were barely observed in them. Furthermore, sequences of
hypervariable regions scarcely changed during 2–5.5 years in both TJN01 and
TJN02. These results indicate that TTV of genotypes 12 and 13 are much different
from the prototype TTV of genotype 1.
The nucleotide sequence data in this paper have been deposited in the DDBJ, EMBL and
GenBank databases under accession Nos. AB028668 and AB028669 for the entire sequences
of TJN01 and TJN02 isolates, respectively, and AB028670–AB028735 and AB037950–
AB037963 for partial sequences of 80 isolates.