Figure 2

Overexpression of cpt1b promotes cardiomyocyte proliferation in zebrafish embryos. (A) A schematic representation of the Tg(myl7:cpt1b-TBFP) construct. (B) A stereo fluorescence image of a 3 dpf wild-type sibling and Tg(myl7:cpt1b-TBFP) embryos. The triangles indicate the embryonic hearts. Scale bar: 200 µm. (C) Whole-mount in situ hybridization analysis of cpt1b expression with WT and cpt1b^OE zebrafish embryos at 3 dpf. The red boxes demarcate enlarged ventral views of the hearts (red triangles). Scale bar: 500 µm. (D) In situ hybridization analysis of cpt1b expression in cryosections of adult WT and cpt1b^OE zebrafish hearts. The red boxes show enlarged views of the denoted regions. Scale bar: 50 µm. (E) Quantitative RT-PCR analysis of cpt1b expression in the hearts of adult WT and cpt1b^OE zebrafish. *** p < 0.001. (F) Representative maximum intensity projection confocal images of dissected hearts from 3 dpf Tg(pcna^mGFP;myl7:H2A-mCherry) and Tg(pcna^mGFP;myl7:H2A-mCherry;myl7:cpt1b-TBFP) embryos. Enlarged single optical section images of the boxed regions are shown on the right. White triangles indicate proliferating cardiomyocytes. Scale bar: 50 µm. (G) Quantitative analysis of proliferating cardiomyocytes in F. * p < 0.05. n = 14–17. (H) Quantification of ventricular areas of adult wild-type and cpt1b^OE zebrafish. n = 9–10. ** p < 0.01.