Figure 7. DNA sequences resulting from template switching of LtrA from Ll.LtrB RNA to exon 1 DNA or RNA.

(A) and (B) Sequences of DNA products resulting from template switching of the Ll.LtrB RT (LtrA protein) from the 5′ end of the Ll.LtrB intron RNA template/Pri c DNA substrate to exon 1 DNA (lane 5) or RNA (lane 6), respectively. (C) Sequences of DNA products resulting from template switching of the Ll.LtrB RT from the 5′ end of Ll.LtrB RNA/primer c substrate to double-stranded exon 1 DNA with a 5′ bottom-strand overhang (AS+9; lane 9). Bands were excised from the gel, cloned, and sequenced, as described in Materials and Methods. The substrate and expected cDNA or DNA product sequences are shown boxed above each set of experimentally determined DNA product sequences. Extra or mutant nucleotide residues are shown in lower case letters. Freq., frequency of occurrence; *, ³²P-label at 5′ end of primer c.