Figure 4.

Expression of 3′-1, 3′-1hsp, and 5′-2 in permanent transgenic lines. (A) Permanent transgenic lines harboring 3′-1, 3′-1hsp, or 5′-2 were generated, and the expression of the transgenes was examined at various developmental stages. Lateral views are shown for embryos at E5.5, E6.5, E6.75, and E7.5; posterior views are shown for E8.0 embryos. The arrow indicate the anterior visceral endoderm. A and P indicate the anteroposterior axis. (B) Transverse sections of E6.5 embryos transgenic for 3′-1hsp. In the embryo harboring 3′-1hsp, X-gal staining was apparent in the posterior epiblast and in the anterior visceral endoderm (arrow).