title: Circular double-stranded forms of TT virus DNA in the liver.
abstract: TT virus (TTV) is an unenveloped, circular, and single-stranded DNA virus commonly infecting human beings worldwide. TTV DNAs in paired serum and liver tissues from three viremic individuals were separated by gel electrophoresis and characterized biophysically. TTV DNAs in sera migrated in sizes ranging from 2.0 to 2.5 kb. TTV DNAs in liver tissues, however, migrated at 2.0 to 2.5 kb as well as at 3.5 to 6.1 kb. Both faster- and slower-migrating forms of TTV DNAs in the liver were found to be circular and of the full genomic length of 3.8 kb. TTV DNAs migrating at 2.0 to 2.5 kb, from either serum or liver tissues, were sensitive to S1 nuclease but resistant to restriction endonucleases, and therefore, they were single-stranded. By contrast, TTV DNAs in liver tissues that migrated at 3.5 to 6.1 kb were resistant to S1 nuclease. They migrated at 3.7 to 4.0 kb after digestion with EcoRI, which suggests that they represent circular, double-stranded replicative intermediates of TTV. When TTV DNAs were subjected to strand-specific primer extension and then amplified by PCR with internal primers, those in serum were found to be minus-stranded DNAs while those in liver tissues were found to be a mixture of plus- and minus-stranded DNAs. These results suggest that TTV replicates in the liver via a circular double-stranded DNA.
authors.affiliation: Immunology Division and Division of Molecular Virology, Jichi Medical School, Tochigi-Ken 329-0498, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Okamoto
authors.forename: M
authors.initials: M
authors.lastname: Ukita
authors.forename: T
authors.initials: T
authors.lastname: Nishizawa
authors.forename: J
authors.initials: J
authors.lastname: Kishimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Hoshi
authors.forename: H
authors.initials: H
authors.lastname: Mizuo
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: Y
authors.initials: Y
authors.lastname: Miyakawa
authors.forename: M
authors.initials: M
authors.lastname: Mayumi
mesh_terms: D001483:Base Sequence; D004266:DNA Virus Infections / Q000097:blood / Q000473:pathology / Q000821:virology; D004267:DNA Viruses / Q000235:genetics*; D004270:DNA, Circular; D004279:DNA, Viral; D006518:Hepatitis Viruses / Q000235:genetics*; D006525:Hepatitis, Viral, Human / Q000097:blood / Q000473:pathology / Q000821:virology; D006801:Humans; D008099:Liver / Q000473:pathology / Q000821:virology; D008969:Molecular Sequence Data
chemical_list: D004270:DNA, Circular; D004279:DNA, Viral