Figure 6.

Activin A enhances ESC contribution to chimeras generated by blastocyst injection. (A) Experimental design. We treated 4-cell embryos without zona in KSOM including Activin A and then performed the blastocyst injection to test whether Activin A can affect the contribution of ESCs to chimeras. (B) The ESC colonies (left panel, bright field; right panel, DsRed). Scale bar, 20 μm. (C) ESC-injected embryos at E4.5. Scale bar, 20 µm. (D) Nanog immunostaining in E4.5 chimeric embryos after blastocyst injection. Nuclei were stained with DAPI (Blue). Scale bars, 20 μm. (E) Summary of ESC (DsRed) contribution to E4.5 embryos. P < 0.05 by Chi-square test. The high group indicates that DsRed ESCs almost overlaid Nanog-positive cells as shown in the top panel of Fig. 4D, and others are included in the low group. (F) Chimeric embryos at E10.5. Scale bar, 500 mm. (G) Average ESC contribution to chimeric embryos at E10.5 using ImageJ software. *P < 0.05 by ANOVA. (H) Summary of ESC (DsRed) contribution to E10.5 chimeric embryos. P < 0.05 by Chi-square test