title: Genomic and evolutionary characterization of TT virus (TTV) in tupaias and comparison with species-specific TTVs in humans and non-human primates.
abstract: TT virus (TTV) was recovered from the sera of tupaias (Tupaia belangeri chinensis) by PCR using primers derived from the noncoding region of the human TTV genome, and its entire genomic sequence was determined. One tupaia TTV isolate (Tbc-TTV14) consisted of only 2199 nucleotides (nt) and had three open reading frames (ORFs), spanning 1506 nt (ORF1), 177 nt (ORF2) and 642 nt (ORF3), which were in the same orientation as the ORFs of the human prototype TTV (TA278). ORF3 was presumed to arise from a splicing of TTV mRNA, similar to reported human TTVs whose spliced mRNAs have been identified, and encoded a joint protein of 214 amino acids with a Ser-, Lys- and Arg-rich sequence at the C terminus. Tbc-TTV14 was less than 50% similar to previously reported TTVs of 3.4-3.9 kb and TTV-like mini viruses (TLMVs) of 2.8-3.0 kb isolated from humans and non-human primates, and known animal circoviruses. Although Tbc-TTV14 has a genomic length similar to animal circoviruses (1.8-2.3 kb), Tbc-TTV14 resembled TTVs and TLMVs with regard to putative genomic organization and transcription profile. Conserved motifs were commonly observed in the coding and noncoding regions of the Tbc-TTV14 genome and in all TTV and TLMV genomes. Phylogenetic analysis revealed that Tbc-TTV14 is the closest to TLMVs, and is closer to TTVs isolated from tamarin and douroucouli than to TTVs isolated from humans and chimpanzees. These results indicate that tupaias are naturally infected with a new TTV species that has not been identified among primates.
authors.affiliation: Immunology Division and Division of Molecular Virology, Jichi Medical School, Tochigi-Ken 329-0498, Japan1.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okamoto
authors.affiliation: Immunology Division and Division of Molecular Virology, Jichi Medical School, Tochigi-Ken 329-0498, Japan1.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nishizawa
authors.affiliation: Immunology Division and Division of Molecular Virology, Jichi Medical School, Tochigi-Ken 329-0498, Japan1.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: First Department of Internal Medicine, Yamanashi Medical University, Yamanashi-Ken 409-3898, Japan2.
authors.forename: Akio
authors.initials: A
authors.lastname: Tawara
authors.affiliation: Immunology Division and Division of Molecular Virology, Jichi Medical School, Tochigi-Ken 329-0498, Japan1.
authors.forename: Yihong
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Institute of Immunology, Tokyo 112-0004, Japan3.
authors.forename: Junichi
authors.initials: J
authors.lastname: Kishimoto
authors.affiliation: Hepatology Institute, People's Hospital, Peking University, Beijing 100044, People's Republic of China4.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D004279:DNA, Viral / Q000097:blood; D016679:Genome, Viral; D006801:Humans; D008969:Molecular Sequence Data; D013045:Species Specificity; D022783:Torque teno virus / Q000145:classification / Q000235:genetics*; D014417:Tupaia / Q000821:virology*
chemical_list: D004279:DNA, Viral