Figure 4. Agarose gel electrophoresis of RT–PCR products. RNA was derived from HEK293 cells transfected with the wildtype c.1183+5 G-allele plasmid construct (lane 1), the mutant c.1183+5 A-allele plasmid construct (lane 2) and the empty pSPL3 vector (lane 3). M, size ladder (100 bp ladder, Fermentas, St. Leon-Rot, Germany). The RT–PCR for the empty pSPL3 vector gives rise to a PCR product of 263 bp. Exon 12 of the PAX6 gene comprises 151 nucleotides.