FIG. 1.

High Grp78 promoter activity in blastocysts requires the ERSE. (A) Schematic representation of 3kb/LacZ and the two internal deletion mutants D170/LacZ and D300/LacZ. The locations of the TATA box, ERSE, and the CRE element are indicated. Additional CCAAT sequences and their orientations with respect to the TATA element are represented by arrows. The lollipop symbols indicate the occurrence of GC-rich sequences similar to Sp1 binding sites. The deleted regions are indicated by dashed lines. (B) Whole-mount β-gal staining of E3.5 embryos of 3kb/LacZ, D170/LacZ, and D300/LacZ TG mice and their nontransgenic (non-TG) siblings. Pictures were taken under a bright field. Scale bar, 50 μm.