[Transforming activity of the DNA from human hepatoma cells. The transcription of integrated viral sequences and their cloning]. / Transformiruiushchaia aktivnost' DNK kletok gepatomy cheloveka. Transkriptsiia integrirovannykh virusnykh posledovatel'nostei i ikh klonirovanie.

ABSTRACT

A monolayer culture of mouse fibroblasts, line NIH/3T3, was transformed by DNA from human hepatoma cell line PLC/PRF/5. The resulting lines of transformed cells differ in their growth characteristics and are capable of producing tumors in nude mice. DNA of these cell lines was found to contain integrated sequences of human DNA and hepatitis B virus DNA. Analysis of transcription showed the amount of virus-specific RNA in the original cell line PLC/PRF/5 to be 20 times as large as in one of the transformed lines. Fragments of DNA of the transformed cells containing virus sequences were cloned, and 400,000 clones were obtained. A clone was identified the insert of which contains a portion of viral genome.