Determination of a putative recombinogenic human hepatitis B virus sequence and its binding cellular protein.
Previously, we reported that C4BglII196, a 196-base pair subgenomic fragment of hepatitis B virus (HBV) covering its precore region, enhances in vitro recombination in the presence of extracts from actively dividing cells (Hino, O., et al. Proc. Natl. Acad. Sci. USA, 88:9248-9252, 1991). The results indicated that HBV may play some role in causing genomic instability during chronic hepatitis. In the present study, we showed that 15AB, a 60-base pair subgenomic fragment of HBV DNA (nucleotides 1855-1914) within C4BglII196 is indispensable for enhancement of in vitro recombination, using the mouse leukemia cell 70Z/3, as the cellular extract source. 15AB, thought to be the encapsidation signal of HBV pregenomic RNA and U5-like retrovirus long terminal repeat, was found to bind specifically to an approximately 100 kDa protein of 70Z/3 by southwestern blotting. Production of a mutation in the 15AB region decreased both its binding activity to 100 kDa protein and the in vitro recombination activity. Our present results thus suggest that 15AB might be a recombinogenic sequence and the 100-kDa protein may be a putative recombinogenic protein in eukaryotes, triggering genomic instability and facilitating carcinogenesis.
Department of Experimental Pathology, Cancer Institute, Tokyo, Japan.
K
K
Kajino
Y
Y
Hotta
O
O
Hino
D001483:Base Sequence; D004273:DNA, Neoplasm / Q000378:metabolism*; D004279:DNA, Viral / Q000737:chemistry / Q000378:metabolism*; D006515:Hepatitis B virus / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D011995:Recombination, Genetic; D014407:Tumor Cells, Cultured
D004273:DNA, Neoplasm; D004279:DNA, Viral