Validation of exon and gene expressions in the EGFR/mTOR pathway. (A) Schematic representation of alternative splicing in this pathway. Exons indicated by probeset seqs are shown in red and additional exons that predict complex alternative splicing are shown in violet. The mountain lines indicate the splicing patterns. (B) Gel images showing semi-quantitative RT-PCR performed using undifferentiated P19 cells (Day 0), P19 cells at the neuronal cell stage (Day 7), and P19 cells at the early glial cell stage (Day 10). Each isoform of a transcript is indicated on the right side. (C) Graphical representations of total gene expressions or the proportional changes of alternatively spliced products are shown on the right axis using black lines or on the left axis using colored columns, respectively. After densitometric analyses, the highest amount of total gene expression among three time points was considered as 1.0. Relative amounts of isoforms in total transcripts at each time point were considered as 100%. Error bars indicate the standard error.