Fig 2: Effect of puromycin on hERG and SCN5A cluster distribution.(A) The distribution of the number of mRNA molecules associated in clusters for each transcript evaluated by smFISH in presence or absence (control) of puromycin. (B) Histogram showing the distribution of colocalized particles in clusters as a fraction of total hERG colocalized particles with or without puromycin treatment. (C) Histogram showing the distribution of colocalized particles in clusters as a fraction of total SCN5A colocalized particles with or without puromycin treatment.

Fig 3: Effects of hERG1b silencing on Ito and KV4.2 channels in iPSC-CMs.(A) Effects of hERG1a or hERG1b silencing on KV4.2 channel mRNA expression levels detected by RT-qPCR (mean ±95% CI) in IPSC-CMs. A non-targeting shRNA (scrambled shRNA) is used as a control. (B) Effects of specific hERG1a or hERG1b silencing on KV4.2 channel mRNAs expressed alone in HEK293 cells. (C) Representative family of traces show Ito in presence of control (upper) or hERG1b shRNA (lower). (D) Summary of steady-state current density vs. test potential shows effect of hERG1b shRNA (mean ±SE).10.7554/eLife.52654.042Figure 8—source data 1.KCND2 is not affected by the co-knockdown effect raw data for Figure 8A–B.10.7554/eLife.52654.043Figure 8—source data 2.Ito current is not affected by the silencing of hERG raw data for Figure 8D.

Fig 4: Co-knockdown of IKr and INa by hERG transcript-specific shRNA.(A) Effects of hERG1a or hERG1b silencing on channel mRNA expression levels detected by RT-qPCR (mean ±95% CI) in iPSC-CMs. A non-targeting shRNA (scrambled shRNA) is used as a control. (B) Effects of specific hERG1a or hERG1b silencing on ion channel mRNAs expressed alone in HEK293 cells. (C) Representative family of traces show IKr in presence of control (upper) or hERG1b shRNA (lower). (D) Summary of steady-state current density vs. test potential shows effect of hERG1b shRNA (mean ±SE). (E) Effects of 1b shRNA on peak tail current vs. pre-pulse potential (mean ±SE). (F) Representative family of traces recorded from iPSC-CMs showing effects of hERG1b-specific shRNA compared to control shRNA on peak INa. (G) Summary current-voltage plot of peak INa vs. test potential (mean ±SE). (H) Summary conductance (G)-voltage plot based on data from G (mean ±SE). (I) Late sodium current representative trace in control and 1b shRNA-transfected cells, measured by applying a single pulse protocol of 800 ms. (J) Summary statistics of peak INa showed a decrease upon transfection with hERG1b shRNA (mean ±SE). (K) Late INa measured as the integral from 50 to 800 ms from the beginning of the pulse showed a decrease upon transfection with hERG1b shRNA (mean ±SE).10.7554/eLife.52654.036Figure 7—source data 1.Co-knockdown of transcripts by qPCR raw data for Figure 7A.10.7554/eLife.52654.037Figure 7—source data 2.Specificity of shRNA raw data for Figure 7B.10.7554/eLife.52654.038Figure 7—source data 3.IKr is reduced upon hERG silencing raw data for Figure 7D–E.10.7554/eLife.52654.039Figure 7—source data 4.Reduction of peak INa after hERG silencing raw data for Figure 7G–H.10.7554/eLife.52654.040Figure 7—source data 5.Decrease of INa,late current upon hERG silencing raw data for Figure 7J–K.

Fig 5: Protein expression evaluation.a-f, Pooled data of immunoblots of different proteins from heart homogenates from WT (blue) and TS1 (red) pigs. Each value is represented as median and IQR. Statistical analysis was conducted using two-tailed Mann-Whitney U-test. a, NaV1.5 relative expression in heart homogenates from n = 8 WT animals (minimum 0.81, median 1.00, IQR: 0.93-1.08, maximum 1.19) and n = 8 TS1 animals (minimum 0.83, median 1.09, IQR: 1.00-1.46, maximum 1.72), p = 0.190. b, CaV1.2 relative expression in heart homogenates from n = 8 WT animals (minimum 0.57, median 1.02, IQR: 0.78-1.22, maximum 1.37) and n = 8 TS1 animals (minimum 0.70, median 0.77, IQR: 0.70-1.07, maximum 1.25), p = 0.280. c, RYR2 relative expression in heart homogenates from n = 8 WT animals (minimum 0.82, median 0.97, IQR: 0.84-1.12, maximum 1.35) and n = 8 TS1 animals (minimum 0.55, median 0.88, IQR: 0.59-1.07, maximum 1.23), p = 0.380. d, KV7.1 relative expression in heart homogenates from n = 8 WT animals (minimum 0.73, median 0.97, IQR: 0.84-1.18, maximum 1.39) and n = 8 TS1 animals (minimum 0.45, median 0.66, IQR: 0.47-0.84, maximum 1.01), p = 0.015. e, KV11.1 (hERG) relative expression in heart homogenates from n = 8 WT animals (minimum 0.56, median 0.96, IQR: 0.73-1.24, maximum 1.53) and n = 8 TS1 animals (minimum 0.53, median 0.75, IQR: 0.57-1.47, maximum 2.20), p = 0.570. f, Phospho Thr287 CaMKII / total CaMKII relative expression in heart homogenates from n = 8 WT animals (minimum 0.69, median 0.97, IQR: 0.82-1.21, maximum 1.38) and n = 8 TS1 animals (minimum 1.13, median 1.77, IQR: 1.32-2.77, maximum 4.31), p = 0.002. Panels a to e refer to Source Data Figs. 1 to 5, respectively; Panel f corresponds to Source Data Figs. 6 and 7. Source data