Cloning and analysis of reverse transcript P160 genomes of Abelson murine leukemia virus

Circular duplex reverse transcripts of the genome of a strain of Abelson murine leukemia virus that encodes a 160,000-molecular-weight protein were isolated, cleaved with HindIII restriction endonuclease, and cloned into the unique HindIII site of lambda phage Charon 21A. Recombinant phage clones, some of which were infectious in transfection assays, were found to contain a 789-base-pair region specific for Abelson murine leukemia virus; this region is not found in other strains of this virus. The extra sequence was localized by restriction endonuclease and electron microscopic heteroduplex analysis. Sequence analysis showed no homology at the ends of the extra sequence, implying that it was deleted by an event that did not utilize sequence homology. The sequence of this unique region has an open reading frame through its entirety.