Integration of Viral DNA Sequences in Infected and Transformed Mammalian Cells

Abstract

<p>Adenovirus infects human KB cells leading to cell lysis and production of progeny virus. It also transforms hamster cells which can induce tumors when injected into hamsters. An experimental system, the DNA-DNA reassociation technique was developed to study the integration of viral DNA sequences in infected and transformed cells. This technique detects less than one viral genome per cell.</p> <p>The quantity of viral genome in tumor, transformed and lytically infected cells was measured. While multiple copies (up to 12) of viral DNA sequences per cell were found, the representation of viral genome was incomplete in transformed and tumor cells with a tendancy for the right hand 45% of the Ad 12 genome being deleted.</p> <p>The reiteration frequency of KB cellular DNA adjacent to an integrated viral genome was found to be representative of the cellular genome suggesting that in lytic infections, there are no specific sites. It was also found that the number of integrated viral sequences was enhanced by cellular proliferation as well as by blockage of cell DNA repair system with caffeine.</p>