title: Molecular and biological properties of BK virus-IR, a BK virus variant isolated from a human tumor.
abstract: We describe the molecular and biological properties of BK virus (BKV)-IR, a new BKV variant isolated from a human tumor of pancreatic islets. BKV-IR bears a 253-base-pair (bp) deletion and an 80-bp insertion in the early region of the genome. The deletion abolishes the expression of small-t antigen. The inserted sequences, grouped in four clusters, produce rearrangements in the first and second enhancer elements. They are bound by 12-bp direct repeats and could form a 217-base stem-loop structure suggestive of an insertion sequence. As compared with wild-type BKV, BKV-IR transformed hamster cells with a reduced efficiency and induced ependymomas in hamsters at a lower frequency and with a longer latency period. Tumors induced by BKV-IR, however, showed features of higher malignancy. The possible role of the insertion sequence-like element in transformation by BKV-IR is discussed.
mesh_terms: D007516:Adenoma, Islet Cell / Q000382:microbiology*; D001739:BK Virus / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D002874:Chromosome Mapping; D004262:DNA Restriction Enzymes; D004279:DNA, Viral / Q000235:genetics; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D006801:Humans; D009690:Nucleic Acid Conformation; D010190:Pancreatic Neoplasms / Q000382:microbiology*; D011120:Polyomavirus / Q000502:physiology*; D012091:Repetitive Sequences, Nucleic Acid; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D004262:DNA Restriction Enzymes