Fig. 5

Fibronectin is required for heart regeneration. (A and B) Wild-type embryos (A), or embryos from a cross between hemizygous hsp70:fn^I1?9 and wild-type parents (B), were heat-shocked at 6 h post-fertilization (hpf) at 38 °C for 40 min and imaged at 24 hpf. Wild-type embryos appeared largely normal after this treatment (92.4% normal, 7.6% general dysmorphology, n=303). By contrast 61.4% of embryos from the transgenic cross developed a markedly shortened body axis (n=264). (C and D) In situ hybridization for fn^I1?9 in wild-type (C) and hsp70:fn^I1?9 clutchmate (D) ventricles at 1 day post heat-shock (dphs). (E?H) MHC (Myosin heavy chain; green) staining and collagen staining of hsp70:fn^I1?9 (E and G) and wild type clutchmate (F and H) ventricles at 30 dpa. Three of 10 ventricles of heat-shocked clutchmates showed obvious areas of missing myocardium, compared to 9 of 10 ventricles in hsp70:fn^I1?9 fish. Fisher Irwin exact test, *p<0.05. Black arrows indicate fibrosis. Dashed line indicates approximate resection plane. Scale bars: 50 μm.