Effect of PNA2406 on the splicing of intron2. JAR cells were transfected with PNAs at the indicated concentrations for 24 h and subjected to RT-PCR analysis using extracted total RNA. RT-PCR was performed with primer sets A and H (see Table 2) for 5'-splice site of intron2 in mdm2 pre-mRNA (161 bp) and β-actin (223 bp) (as internal control), respectively. The numbers under the figure indicate the relative amount (normalized to β-actin) of the target mdm2 splicing variant. A, Dose dependent splicing inhibition of intron2 by PNA2406 (1, 2, 4 and 8 μM). 26 PCR cycles was used. B, comparison of PNA2406 with its mismatch PNA (PNA2681, mismatch) holding two mismatches (at 2 μM). 27 PCR cycles was used.