The endogenous reverse transcriptase activity of gibbon ape lymphoma virus: Characterization of the DNA product

Abstract The DNA product of the endogenous reverse transcriptase reaction of Gibbon ape lymphoma virus has been analyzed and characterized. Data show that in simultaneous detection assays in which the type and/or concentration of divalent cation is varied the best yield of rapidly-sedimenting DNA was obtained from reactions containing 1.5 mM Mn 2+ . This yield is ten-fold better than the yield observed at the optimal Mg 2+ concentration (5.0 mM). Evidence is presented to show that DNA synthesized at the optimal concentration of either of these cations consists of large pieces varying in size from 4 to 12S. This DNA hybridizes efficiently to homologous viral RNA (greater than 60% annealing) and protects at least two-thirds of GALV 70S [ 32 P] RNA from ribonuclease digestion. The hybrids formed with homologous viral RNA are stable as evidenced by their thermal elution patterns from hydroxylapatite columns. In contrast, DNA synthesized in reactions in which the concentration of Mn 2+ or Mg 2+ was greater than optimal was predominantly 4S or smaller in size and displayed a low level of hybridization (less than 10%) to homologous viral RNA.