Figure 1 supplement 5

(A, B, F, G) Maximum intensity projection of Tg(myl7:HRAS-EGFP) snai1b^+/+ (A, F) and snai1b^-/- (B, G) hearts at 52 (A, B) and 74 (F, G) hpf. At both timepoints, snai1b^-/- embryos exhibit reduced CM apical cell surface (C, H), increased CM aspect ratio (D, I), and reduced ventricular volume (E, J) compared with snai1b^+/+ embryos. (C, H) snai1b^+/+, N = 190 at 52 hpf, N = 173 at 74 hpf; snai1b^-/-, N = 195 at 52 hpf, N = 178 at 74 hpf. (D, I) snai1b^+/+, N = 183 at 52 hpf, N = 162 at 74 hpf; snai1b^-/-, N = 188, N = 170 at 74 hpf. (E, J) snai1b^+/+, n = 32 at 52 hpf, n = 28 at 74 hpf; snai1b^-/-, n = 27 at 52 hpf, n = 26 at 74 hpf. (K–P) snai1b mutants exhibit no differences in heart rate (K), ventricular ejection fraction (L), or ventricular fractional shortening (M) compared with snai1b^+/+ embryos at 52 hpf (K, snai1b^+/+, n = 28; snai1b^-/-, n = 29; L, snai1b^+/+, n = 33; snai1b^-/-, n = 35; M, snai1b^+/+, n = 28; snai1b^-/-, n = 35), but exhibit reduced heart rate (N), ventricular ejection fraction (P), and ventricular fractional shortening (O) compared with snai1b^+/+ larvae at 74 hpf (N, snai1b^+/+, n = 26; snai1b^-/-, n = 28; P, snai1b^+/+, n = 27; snai1b^-/-, n = 24; O, snai1b^+/+, n = 24; snai1b^-/-, n = 20). Plot values represent means ± S.D.; p-values determined by Mann–Whitney U test. Scale bars: 20 µm. V: ventricle; A: atrium; n: number of embryos; N: number of CMs.