Figure 3

Loss of N-cadherin impairs proliferation and induces premature differentiation of AHF progenitor cells. (A) Representative sagittal section of control and mutant embryos at E9.5 immunostained for Isl1 (green) and phospho-Histone 3 (red); arrows point to Isl1/PiH3 double-positive cells in the OFT and AHF (enlarged image). Nuclei are marked by DAPI. Scale bar, 200 μm. (B) Quantification of cell proliferation indicated by mitotic index in the anterior heart field and neural tube regions of wild-type and mutants at E9.5. Error bars indicate SD, n = 4 experiments, ^**P = 0.01, evaluated by Student's t-test. (C) Representative transverse sections of control and mutant embryos at E9.0 immunostained for Isl1 (green) and cleaved Caspase 3 (red) in outflow tract (OFT) and neural tube (NT). Nuclei are marked by DAPI. Scale bar, 200 μm. (D) Sagittal sections of control and mutant embryos at E9.0 immunostained for cardiac troponin T (cTnT) (red). Note the presence of ectopic cTnT+ cells (arrows) in the AHF. Nuclei are marked by DAPI. Scale bar, 200 μm. (E) Quantification of cTnT+ cells in the AHF of the control and mutant embryos at E9.0. cTnT+ cells within the AHF, the region between OFT and anterior portion of pharyngeal mesoderm were counted. A total of 7-9 serial sections for each embryo were used. Error bars indicate SD, n = 6 embryos. ^***P = 0.001, evaluated by Student's t-test.