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Fig. 4. Reduced number of terminally differentiated cardiomyocytes upon loss of Dkk1. A. Sections of embryos are shown stained for cardiac troponin T (red) to label cardiomyocytes and phosho-histone H3 (PH3, green) lo mark proliferating cells and counterstained with DAPI (blue) to highlight nuclei at the stages indicated. Yellow arrowheads indicate proliferating cardiomyocytes positive for cardiac troponin and phosho-histone H3. B. Cardiac troponin T positive cardiomyocytes were quantified on continuous serial sections of stained embryos. Embryos bilaterally injected with Dkk1 MO showed reduced number of cardiomyocytes at the stages indicated. C. The mitotic index (MI) as defined by the percentage of phosho-histone H3 positive cardiomyocytes is not affected upon Dkk1 MO injection. N = number of independent embryos counted. *p < 0.05, **p < 0.01, with Mann-Whitney rank sum test. Scale bar, 100 μm. |
