Polymerization and RNase H activities of the reverse transcriptases from avian myeloblastosis, human immunodeficiency, and Moloney murine leukemia viruses are functionally uncoupled.

摘要: The functional interaction between the RNA-dependent DNA polymerase and RNase H activities of reverse transcriptases (RTs) were examined using a 272 nucleotide long plasmid-derived RNA transcript primed in specific location. Properties avian myeloblastosis virus (AMV) RT, human immunodeficiency RT Moloney murine leukemia examined. All three enzymes formed stable complexes with primer-template half-lives ranging from about 16 to 41 s. Each enzyme synthesized full-length primer extension products cleaved template at least once during synthesis. Polymerization was then assayed presence challenger that effectively sequestered RTs after one round processive This assay allowed measurement number endonucleolytic cleavages catalyzed by encounter primer-template. Results indicated each cut before dissociating primer-template, whether or not deoxynucleoside triphosphates present allow During synthesis, extent degradation differed among RTs, AMV-RT generating mostly large segments RNA-DNA hybrid, virtually no small cleavage products. Human virus-RT generated more than AMV-RT, but still left much potentially degradable hybrid undigested. demonstrate function is less active polymerization synthesis are strictly coupled.