HS-26 is formed in the absence of AP1/NFE2 binding sites. (Top) Diagram of 4.9-kb wild-type HindIII DNA fragment. Cleavage at HS-26 yields a 3.6-kb band in Southern blots. The probe (▦) and other symbols are the same as in Figure 1. (Bottom) DNase I hypersensitivity in E14.5 fetal liver cells. Genotypes are indicated at the top.