title: Mode of transmission of human T-cell leukemia virus type I (HTLV I) in a human promyelocytic leukemia HL60 cell.
abstract: HTLV-I propagated in IMR90 human diploid fibroblasts was transmitted to human myeloid leukemia HL60 cells at a low efficiency. After co-cultivation for 3 months, the viral genome was detected in 14/48 HL60 cell clones. Among the 14 HTLV-I-infected clones, 8 contained subgenomic fragments alone or in addition to the complete HTLV-I genome. The frequency of deleted proviruses (9/24 total proviruses) was unexpectedly high. Hirt's supernatant of some of the clones harboring complete HTLV-I genome(s) in the chromosome contained both linear and circular HTLV-I proviral DNAs. The circular DNAs were composed of one LTR and 2 LTR closed circular proviruses. These clones produced infectious HTLV-I constitutively, which was proved by transmission of the viral genome into fresh IMR90 cells by co-cultivation. However, in these clones, re-integration of extrachromosomal provirus into their own chromosomes was not observed.
mesh_terms: D002460:Cell Line; D002472:Cell Transformation, Viral; D002872:Chromosome Deletion; D004270:DNA, Circular / Q000032:analysis; D004279:DNA, Viral / Q000032:analysis; D017977:Deltaretrovirus / Q000235:genetics / Q000254:growth & development*; D005814:Genes, Viral; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D012091:Repetitive Sequences, Nucleic Acid; D014779:Virus Replication
chemical_list: D004270:DNA, Circular; D004279:DNA, Viral