Fig. 3.

Polyadenylation of HPV16 late transcripts in vivo. (A) Agarose gel electrophoresis of products of 3′RACE using nested L1 gene-specific primers and cDNA reverse transcribed from polyadenylated W12 cell RNA. Track 1: DNA, marker track 2: undifferentiated RNA without reverse transcriptase, track 3: differentiated RNA without reverse transcriptase, track 4: undifferentiated RNA with reverse transcriptase, track 5: differentiated RNA with reverse transcriptase. The arrowhead indicates the major product corresponding to polyadenylation at LP2 and the arrow a minor product indicating polyadenylation at LP1. (B) Diagram of the HPV16 genome showing the approximate positions of the early and late polyadenylation sites. Below is shown the region of genome sequence from 7251 to 7350 containing the two active late polyadenylation sites. Grey boxes indicate the polyadenylation signals. Arrowheads indicate the cleavage sites.