Figure 2. A phosphomimetic SRF mutant induces concentric cardiac hypertrophy in vivo.

A, Flag-tagged SRF WT and mutant proteins were expressed by adeno-associated virus (AAV) serotype 9 vectors that direct expression under the control of the cardiac myocyte-specific chicken cardiac troponin T promoter (AAV9.SRF).²⁴ B, Representative anti-SRF immunoblot of heart extracts from C57BL/6 mice injected i.p. as neonates with 10¹¹ vg AAV9.SRF WT, S103A, or S103D or AAV9.GFP control. Equal loading of samples was confirmed by Ponceau S total protein staining (not shown). C, Left ventricular (LV) anterior wall thickness (LVAW) and wall thickness to interior diameter ratio in diastole [(LVPW+LVAW)/LVID;d] were measured by M-mode echocardiography (Figure III and Table I in Data Supplement). D, left ventricular mass (indexed to body weight) based upon B-mode echocardiographic data. n = 18-27 for C,D. E, Tissue sections stained with wheat germ agglutinin were used to measure myocyte cross-section area. Bar – 25 μm. n = 5-9. F, Cardiac myocytes acutely isolated from AAV-injected mice were measured for length and width using bright-field microscopy. Bar – 25 μm. n = 4-6. p-value symbols: * vs. GFP; ^† vs. SRF WT; ^‡ vs. SRF S103A; *,^†,^‡ p < 0.05; ^††,^‡‡ p < 0.01; ***,^††† p < 0.001. Bars indicate mean +/− s.e.m. Data passed D’Agostino-Pearson omnibus (K2) testing and were analyzed by one-way ANOVA and Tukey Post-hoc testing.