SMN1 and proximal spinal muscular atrophy: Quantitative RT-PCR analysis confirmed our previous results regarding the transcriptional activation of endogenous SMN2 in transfected SMA iPSCs, and showed that TALE-TFs 1 + 3 + 5 were the most effective of all TALE-TF combinations employed in our experiment: respective increases in the expression of full-length SMN and SMN lacking exon 7 (SMNΔ7 isoform) by >3-fold and >2.5-fold were observed in SMA iPSCs treated with this combination (Fig. 5B).