Replicating DNA of Adenovirus Type 2

Abstract

We have investigated the nature of the DNA synthesized in KB cells 24 h after infection with adenovirus type 2 (ad. 2). Cellular DNA synthesis being strongly depressed, a new molecular form of ad. 2 DNA could be detected in such cells in addition to mature viral DNA. This new form, referred to as DNA-R, is preferentially labelled after short pulses of 3H-thymidine, while the radioactive label can be chased into mature viral DNA. The sedimentation properties of DNA-R are those expected for linear replicating molecules having 1–2 times the molecular weight of mature viral DNA. As a result of being partly single-stranded, these molecules can be separated from mature viral DNA by chromatography on benzoylated-naphthoylated DEAE-cellulose. Purified DNA-R was examined under the electron microscope and found to consist of Y-shaped molecules. Thus DNA-R has the properties expected for linear monomeric molecules of ad. 2 DNA replicating undirectionally.