Figure 6

Gata4 induces the expression of Ens-1 in vivo. (A) Nanog, Gata4 and Ets2 transcripts detected by in situ hybridization in stage XIII (EG) chick blastula. Sections highlight specific expression either in the epiblast or in the hypoblast (black arrow). (B) In situ hybridization in chick stage XIII (EG) blastula A and in stage 5 (H&H) gastrula B. Sections show Ens-1 expression both in the epiblast (black arrow on a, enlargement on a') and in the hypoblast (red arrow in a, enlargement on a') at blastula stages, and later, at gastrulation, at the border of neural and non neural ectoderm (black arrow on b') and in the extraembryonic mesoderm (red arrow on b", enlargement below). Dotted lines indicate sections' level. (C) Epiblasts of preprimitive streak chicken embryos were electroporated for the ectopic expression of GFP alone (A-C) or conjointly with the transcription factors Gata4 (D-F), Ets1 (G-I) and CP2 (J-L). Ens-1 transcripts were detected ten hours later by in situ hybridization. Results obtained in 10 out of 19 electroporated embryos with Gata4 (F), in 4 out of 17 with CP2 (L), in 13 out of 13 with Ets1 (I) and in 12 out of 12 (C) with GFP alone.