Total RNA was extracted using TRIzol Reagent (Invitrogen), and cDNA was generated using SuperScript III Reverse Transcriptase (ThermoFisher). The qPCR reaction was performed by SsoAdvanced Universal SYBR Green Supermix (Bio-Rad) and QuantStudio3 real-time PCR system (Applied Biosystems). The full-length SMN2 transcripts were amplified using the primer set: (forward, 5′-GCTATCATACTGGCTATTATATGGGTTTT-3′; reverse, 5′-CTCTATGCCAGCATTTCTCCTTAAT-3′). The ∆7 SMN2 transcripts were amplified using the primer set: (forward, 5′-TCTGGACCACCAATAATTCCCC-3′; reverse, 5′-ATGCCAGCATTTCCATATAATAGCC-3′). The expression of GAPDH was measured using the primer set (forward, 5′-GCAAATTCCATGGCACCGT-3′; reverse, 5′-AGGGATCTCGCTCCTGGAA-3′). The relative expression of full-length SMN2 to GAPDH or ∆7 SMN2 was calculated, and normalized to the non-treated cells with the ∆∆Ct algorithm.