Frog virus 3 deoxyribonucleic acid.

SUMMARY DNA extracted from frog virus 3 has a GC mol fraction of about 0"56. The mol. wt. of the DNA is about Ioo x I@ (97 × IO 6 by neutral sucrose gradient sedimentation; IO2 × IO 6 from renaturation kinetics). Analysis by neutral sucrose sedimentation indicated that the DNA exists as a single heteroduplex in the virus particle. Alkaline sucrose gradient sedimentation indicated that single strand alkali labile interruptions probably occur in both strands of the heteroduplex. Renatura-tion kinetic analysis also indicated that about 7 ~ of the genome contains repeated sequences. Quantitative analyses of DNA-DNA homology showed no sequence homology between frog virus 3 DNA and the DNA extracted from iridescent virus types 2, 6 or 9. This lack of sequence homology reflects the markedly distinct profiles on acrylamide gels of the structural polypeptides of frog virus 3 and the iridescent viruses.