E2-induced alternative splicing of endogenous genes. A) Partial exon-intron structure of genes that were alternatively spliced upon E2 treatment. Exon-intron structure of wild type and spliced variants are shown. B) qRT-PCR analyses of AXIN-1a and AXIN-1b in untreated and E2 treated MCF-7p and MCF-7AKT cells. Statistically significant increase in AXIN-1a and AXIN-1b in E2 treated cells compared to untreated cells is indicated (p<0.05). Down-regulation of AXIN-1a expression in MCF-7AKT cells compared to MCF-7p cells is indicated (**p=0.04). C) E2 increases the levels of Δ3,4 FAS but not total FAS. qRT-PCR was performed using primers that amplify the common exon 9 (for total FAS) or spanning exons 2 and 5 junction and exon 6. *p<0.02 untreated versus E2 treated condition. D) The effect of E2 and AKT on alternative splicing of FGFR2. E2 increased the expression of C1 isoform (p=0.0001) but reduced C3 levels in MCF-7p cells (p=0.004). Basal FGFR2 C1 levels were elevated in MCF-7AKT cells compared to MCF-7p cells (p=0.05).