Fig. S12

Cardiac performance after ablation of tbx5a-derived cells.

tbx5a⁺ ventricular cardiomyocytes were genetically ablated in tbx5a:CreER^T2;vmhcl:loxPtagBFP- loxP-mCherry-NTR double transgenic zebrafish. Recombination was induced by administration of 4-Hydroxytamoxifen (4-OHT) at 1 and 2 days postfertilisation. Animals were divided into two groups. Cell ablation was induced in one group by administration of Metronidazole (Mtz) from 4 to 7 dpf. Videos were acquired at 7 dpf, immediately after the last Mtz treatment. a–d are still images from the videos from two Mtz-treated (from a total of 4) and two non-treated (from a total of 3) animals. Shown are lateral views of the heart, the head is to the left. The ventricle is outlined in yellow. Note the irregular shape and overall smaller area in Mtz-treated hearts. e The maximum (diastolic) and minimum (systolic) ventricular area was measured to determine ventricular function. P= 0.0348 by a two-tailed t-test. Deficient contraction was detected upon Mtz treatment. f Percentage of survival at 5 weeks post fertilization (wpf); mean±s.d **P<0.01; *P<0.05; ns, nonsignificant by one-way ANOVA followed by Tukey’s multiple comparisons test. Each point represents the survival percentage of a group comprising 14-22 fish each. –Mtz: same stages control fish; sib+Mtz= tbx5a:CreER^T2 and vmhcl:loxP-tagBFP-loxPmCherry- NTR single transgenic siblings; Tg+Mtz= tbx5a:CreER^T2;vmhcl:loxP-tagBFPloxP- mCherry-NTR double transgenic fish. g Assessment of ventricular Fractional Volume Shortening (FVS) by echocardiography at 44 dpf. Shown are individual measurements as well as mean±s.d; ns, P = 0.6262 by two-tailed unpaired t-test; n=7 for – Mtz group and n=3 for + Mtz group