Relationship of mRNA from Productively Infected Cells to the Complementary Strands of Adenovirus Type 2 DNA

Abstract

The complementary strands of adenovirus type 2 (Ad2) DNA were separated by buoyant density gradient centrifugation with poly (U, G). The complementary strand DNA was shown to remain intact through the course of strand separation. The l-strand of Ad2 DNA, appearing in the less dense complex with poly (U, G) in neutral CsCl density gradients, was shown to have a buoyant density in alkaline (pH 12.5) CsCl density gradients which is 2 to 3 mg per ml greater than that of its complement (h-strand). Renaturation of purified complementary strand DNA was observed only in mixtures of h- and l-strand DNA, and then with the second-order reaction rate expected for Ad2 DNA. Hybridization of the complementary strands of Ad2 DNA with cytoplasmic mRNA isolated from infected HeLa cells was performed in liquid phase and analyzed by hydroxylapatite chromatography. Before viral DNA synthesis (6 h after infection), 13 to 18% of the h-strand and 30 to 35% of the l-strand were represented in viral mRNA. Late (18 h) after infection the mRNA represented 20 to 25% and 63 to 68% of the h- and l-strands, respectively. Most, if not all sequences present in viral mRNA before viral DNA synthesis were also present in the cytoplasm late in infection.