RNA-DNA Covalent Bonds Between the RNA Primers and the DNA Products Formed by RNA Tumor Virus DNA Polymerase

摘要: Initiation of DNA synthesis by endogenous RNA primer molecules was studied with three different tumor viruses. The influence the method virus disruption on observed RNA-DNA bonds ascertained. Ether disrupted virions both murine leukemia (MuLV) and B77 strain avian sarcoma (B77 virus) have rC-dC rA-dA covalent linkages between primers newly synthesized DNA. None 14 other possible were formed. Ether-disrupted myeloblastosis (AMV) rU-dC linkages. In contrast, work reported herein from laboratories shows that Nonidet P-40 (NP-40)-disrupted all viruses only junction. Studies particles which first ether then treated NP-40 indicated detergent treatment disallowed formation ribopyrimidine-dC internucleotide bond. same transfers are found AMV in presence or absence actinomycin D, where single-stranded is This finding consistent notion virtually significant been recognized. contrast to mature virions, transfer experiments ether-disrupted early harvest (5 min) MuLV showed bond; bond absent. short-time contains a significantly higher proportion infectious than 24-h harvests. Also, since appreciably more homogenous MuLV, it concluded linkage initiation event biochemical standpoint.