Adenovirus E1A oncogene induces re-replication of cellular DNA and alters DNA replication dynamics

Human adenovirus type 5 oncogene E1A was shown to induce massive re-replication of cellular DNA in late S phase. Using DNA combing analysis, it was shown that DNA replication dynamics including replicon length, fork velocity and inter-origin distance were dramatically altered in E1A expressing cells as compared to that of normal serum stimulated cells. It was also shown that c-Myc that is induced in E1A expressing cells is essential for the efficient entry of E1A expressing cells into S phase. Serum starved cells were infected with an adenovirus expressing only the transforming E1A protein, and with Adbeta-galactosidase (control) were analyzed by flow cytomery. DNA prepared from such cells were analyzed by DNA combing analysis and data obtained were examined statistically. Requirement of Myc in E1A induced S phase entry was also examined by using antisense Myc vector.