Characterization and cloning of the Kirsten murine leukemia virus genome

We have characterized the intracellular and circular unintegrated proviral DNA species of Kirsten murine leukemia virus by restriction mapping using the Southern blotting technique. These studies show the 8.5 kilobase pair genome to possess long terminal repeats (0.5 kilobase pairs in length) which are indistinguishable from those of the derivative Kirsten murine sarcoma virus. In addition, we have identified a 3'-located region in Kirsten murine leukemia virus which is very similar to the putative leukemogenic region of Gross murine leukemia virus. We also report the cloning of the leukemia virus genome using DNA obtained from the endogenous reverse transcriptase reaction of detergent disrupted virions.