The viral DNA replication complex of adenovirus 12

Abstract

After infection of human embryo kidney cells in a resting state with adenovirus 12, viral DNA synthesis began at 24 hr post infection (p.i.) and reached its peak at 32 hr p.i. Both parental and nascent DNAs were present in the M-band fraction of nuclei of infected cells at 32 hr p.i. The DNA synthesizing activity in vitro with isolated nuclei and the M-band fractions began to increase at 24 hr p.i. and reached its maximum at 32 hr p.i. The DNA synthesized in vitro was viral as revealed by DNA-DNA hybridization. Electron microscopic autoradiograms of infected cells revealed that silver grains were found in association with bandlike inclusion bodies in the interior of the nucleus and did not associate with the nuclear membrane. After chase for 1 hr, most of the grains were found in the same state. These observations indicate that the viral DNA replication complex is formed in the interior of the nucleus and contained in the M-band fraction after fractionation.