Complete sequences of two highly divergent European isolates of TT virus

TT virus is a virus distantly related to the Circoviridae family. We report here the complete genome characterization of two European human isolates ( T3PB and TUPB) using a new and simple protocol for sequencing CC-rich genom ic regions, Sequence analysis confirmed the existence of two major ORFs, of a CAV-like VP2 motif in ORF2 and of potential stem-loop structures in non- coding regions. Phylogenetic analyses based on complete genomic sequences o f human isolates suggested that three different lineages exist at least. Th e first lineage includes genotypes 1, 2, and 3, and two other lineages incl ude viruses related to the Japanese SANBAN and to the North American TUS01 isolates respectively. Sequence comparison made it possible to assign strai n T3PB to genotype 3, and strain TUPB to the TUS01 group. Consequently, thi s study reports the first full-length sequence of a genotype 3 isolate and demonstrates that viruses belonging to the TUS01 lineage are present in the Old Word. (C) 2000 Academic Press.