Figure 2. RT-PCR revealed sT-ag-expressing cell lines contained a transcript with a partial duplication of T-ag exon 2 sequences. (A) SV40-specific RT-PCR products of seven cell clones (lane 1 to 7) generated with the PCR-primers g and w that bind upstream and downstream the 346 nt T-ag intron. Lane 0 shows the 808 nt PCR product when the SV40 T-ag DNA was used as template—RT-PCR using the T-ag pre-mRNA as template generates the same PCR product. The T-ag mRNA (462 nt product) but not the T-ag pre-mRNA/genomic DNA was detected in all clones and an additional 609 nt band, but no 945 nt (609 nt + 346 nt) band, was detected in the sT-ag expressing clones. (B) Organisation and primer binding sites of the early T-ag pre-mRNA. (C) Organization and primer binding sites of the spliced sT-ag mRNA. (D) Organization and primer binding sites of the spliced T-ag pre-mRNA.