Figure 1. Cardiac-specific, FLAG-tagged F1759A-Na_V1.5–expressing TG mice.

(A) Schematic of the binary transgene system. αMHC-rtTA is the standard cardiac-specific, reverse tetracycline–controlled transactivator system. The αMHC_MOD construct is a modified αMHC promoter containing the tet-operon (tet-O) for regulated expression of FLAG-tagged, lidocaine-resistant Na_V1.5 (FLAG-lido-NaV). (B) Quantification of mouse Scn5a and human SCN5A transcripts in ventricle and atrium of F1759A-dTG mice using qPCR. Results are presented as fold difference for each gene against actin by use of 2^–ΔΔCT method, followed by normalization to expression of either mouse Scn5a or mouse Scn5a and human SCN5A determined in NTG mice. n = 3 NTG and n = 4 F1759A-dTG mice in each group. (C) Immunostaining of F1759A-dTG mice cardiomyocytes with or without anti-FLAG antibody and FITC-conjugated secondary antibody. Images were obtained with confocal at ×40 magnification. (D and E) Anti-FLAG, anti-Na_V1.5, and anti-tubulin antibody immunoblots of cardiac homogenates showing FLAG epitope–tagged Na_V1.5 expression in ventricle (D) and atrium (E) of single TG and dTG mice in the absence of doxycycline-impregnated food.