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. 2015 Jun 24;107(4):466–477. doi: 10.1093/cvr/cvv184

Figure 7.

Figure 7

AnkB-188 knockdown decreases the expression and subcellular localization of NCX and elicits arrhythmic contractions. (A) Isoform-specific siRNAs were designed to exons unique to AnkB-188 and AnkB-212. (B) Knockdown of isoform mRNA was assessed by qt-PCR using primer sets unique to each isoform (black arrows). qt-PCR values were normalized to GAPDH mRNA expression and expressed as a percentage of isoform expression in untransfected cardiomyocytes, which was set to 100%. Grey bars represent isoform mRNA expression targeted by the siRNAs. Black bars represent mRNA expression of controls and the other isoform. (C) Immunoblot analysis of AnkB-188, AnkB-212, and NCX in control and siRNA-treated cardiomyocytes. Pan-actin immunoblot demonstrates equal protein loading. (D) Immunofluorescent localization of NCX and ankyrin-B in siRNA-treated cardiomyocytes. Regions boxed in white are magnified in the side panel. (E) AnkB-188 or AnkB-212 siRNA treatment precipitates irregular cardiomyocyte contractions. The left panel presents representative contraction rhythms of untransfected and transfected cardiomyocytes. The right panel presents the summary data. Box-and-whisker plots represent the difference in time between individual contractions and the average contraction time over a 30 s interval. Sample size is untransfected: 6, scramble: 7, B188-siRNA: 7, and B212-siRNA: 5. #P-value » 0.05 and *P-value < 0.05 compared with the untransfected.