Fig. 1

Runx1-Citrine becomes strongly expressed in the heart after cryo-injury. (A-D″) Immunohistochemistry for Runx1-Citrine (GFP antibody) and the myocardial marker MF20 at different time points after cryo-injury. (A,A′) Citrine expression in the uninjured hearts was confined to a small number of cells scattered around the heart (arrowheads). (B-B″) At 1 dpci, the epicardium was Citrine positive (arrowheads). Bright blood cells were visible within the wound and there was dim expression of Citrine overlapping with MF20 (B″). (C-C″) At 3 dpci, the epicardium, endocardium (arrowheads) and other wound cells were positive for Citrine. In addition, the myocardium in the border zone next to the wound was highly Citrine positive (C″). (D-D″) Expression of Citrine diminishes at 14 dpci but is still visible, especially in the myocardium (D″). (E,E′) In situ hybridisation for itga2b with immunohistochemistry for Runx1-Citrine and nuclear marker DAPI. Arrowheads indicate overlap of Runx1-Citrine with itg2b mRNA, indicating that thrombocytes are positive for Runx1-Citrine. a, atrium; ba, bulbus arteriosus; dpci, days post cryo-injury; en, endocardium; ep, epicardium; v, ventricle; w, wound. Scale bars: 100 μm.