Fig. 3.

Gata4 is required for the proliferation but not for the survival of atrial septum progenitors. (A–D) BrdU staining was performed in Gli1^Cre-ERT2/+;Gata4^fl/+ embryos (B and D) and Gli1^Cre-ERT2/+ embryos (A and C) at E9.5. (E) The percent of cardiac progenitors that incorporated BrdU in the pSHF and the DMP region (typical regions are shown as the boxed areas in C, D, H, and I) was calculated in a total of 500 cells, counted in five serial sections. Data are presented as mean ± SEM, n = 3 or 4; *P < 0.05. (F–I) TUNEL staining was performed in Gli1^Cre-ERT2/+;Gata4^fl/+ embryos (G and I) and Gli1^Cre-ERT2/+ littermate control embryos (F and H) at E9.5. (Magnification: 100× in A, B, F, and G; 200× in C, D, H, and I.) A, atrium; V, ventricle.