Simian virus 40 deoxyribonucleic acid synthesis: analysis by gel electrophoresis

An agarose-gel electrophoresis technique has been developed to study simian virus 40 deoxyribonucleic acid (DNA) synthesis. Superhelical DNA I, relaxed DNA II, and replicative intermediate (RI) molecules were clearly resolved from one another for analytical purposes. Moreover, the RI molecules could be identified as early or late forms on the basis of their electrophoretic migration in relation to that of DNA II. The technique has been utilized to study the kinetics of simian virus 40 DNA synthesis in pulse and in pulse-chase experiments. The average time required to complete the replication of prelabeled RI molecules and to convert them into DNA I was approximately 10 min under the experimental conditions employed.