Fig. 7. Intravenous AAV-mediated delivery of BacNa_v results in robust transgene expression in ventricles and atria, but not the SAN of the adult mouse heart.

a, b Representative images of transverse ventricular (a) and atrial (b) sections of the mouse heart six weeks after tail-vein injection of 1 × 10¹² vg of scAAV9-MHCK7-h2SheP-HA showing robust BacNa_v expression in cardiomyocytes. c, d Representative images of the sinoatrial node (SAN) and surrounding atria of mice injected with 1 × 10¹² vg of scAAV9-MHCK7-GFP (c) or scAAV9-MHCK7-h2SheP-HA (d). The SAN areas are delineated with white dashed lines identified from the robust expression of HCN4 and absence of Cx43. Note minimal transgene expression in the SAN. e Quantified areas of HCN4⁺,HA⁺, GFP⁺, or Cx43⁺ area relative to F-actin⁺ area in the SAN, atrial, and ventricle (n = 6 animals, 6 sections of each tissue per animal were imaged for quantification. ****P < 0.0001; ***P = 0.0006, SAN vs. Atria in GFP groups; ***P = 0.0002, SAN vs. Ventricle in GFP groups; ***P = 0.0002, SAN vs. Ventricle in Cx43 groups). Error bars indicate s.e.m; statistical significance in e was determined by one-way ANOVA, followed by Tukey’s post-hoc test to calculate P-values. Source data are provided as a Source Data file.