Fig. 4.

Gata4 regulates cell-cycle progression of pSHF. (A–D) IHC staining for H3S10 was performed in the pSHF of the Gata4^{Gli1Cre-ERT2/+} embryos (B and D) and in Gli1^Cre-ERT2/+ embryos (A and C) at E9.5. (E) The black arrowheads indicate typical cells in M phase; the red arrowheads indicate typical cells in G2 phase. (F) The percentage of H3S10⁺ cardiac progenitors was calculated in 500 cells in the pSHF and the DMP region (typical regions are shown as the boxed areas in C and D) counted in five serial sections. Data are presented as mean ± SEM, n = 3 or 4; *P < 0.05. (G–J) IHC staining for Cdk4 was performed in Gli1^Cre-ERT2/+;Gata4^fl/+ embryos (H and J) and in Gli1^Cre-ERT2/+ embryos (G and I) at E9.5. (K) The percentage of Cdk4⁺ cardiac progenitors was calculated in 500 cells in the pSHF and the DMP region (typical regions are shown as the boxed areas in I and J) counted in five serial sections. Data are presented as mean ± SEM, n = 3 or 4; *P < 0.05. (L) Expression levels of cell-cycle–related genes in the pSHF of mouse embryos at E9.5 were measured by real-time PCR. Data are presented as mean ± SEM, n = 3; *P < 0.05. (Magnification: 100× in A, and B; 200× in C, and D; 400× in E; 150× in G and H; 300× in I and J.)