FIG. 1.

(A) Diagram of the FV genome representing unspliced and spliced mRNAs derived from a major promoter (P) at the 5′ long terminal repeat and an internal promoter (IP). (B) Splice sites for pol mRNA shown with respect to the open reading frames of Gag and Pol. Pol is synthesized by a −1 frameshift at the 3′ end of a gag gene. There is a 541-nt overlap in the two exons, shown in gray, which includes three glycine-arginine-rich (GR) boxes at the C terminus of Gag, shown in black.