Nucleotide sequence analysis of the transforming region and large terminal redundancies of Moloney murine sarcoma virus.

The sequence of the transforming region of the Moloney murine sarcoma virus genome has been determined by using molecularly cloned viral DNA. This region, 3.6 to 5.8 kilobase pairs from the left end of the molecule, contains the entire cellular insertion (src) sequence as well as helper viral sequences including the large terminal repeat (LTR). On the viral RNA strand, a long (1224 bases) open reading frame commenced to the left of the src-helper virus junction and terminated at a point 58 nucleotides into helper viral sequences to the right of src. Possible promoter and acceptor splice signals were detected in helper viral sequences upstream from this open reading frame. On the antiviral RNA strand, several promoter-like sequences, including one within the src region itself, were identified. However, no open reading frame downstream from these promoters was detected in the antiviral RNA strand. The LTR was found to contain promoter-like sequences as well as LTR was found to contain promoter-like sequences as well as mRNA capping and polyadenylylation signals. In addition, it possessed an 11-base inverted terminal repeat at each end. Thus, the structure of the Moloney murine sarcoma virus genome with an LTR at each end resembles that of prokaryotic transposable elements.