EKLF is required for β-globin–transgene expression in the fetal-adult stage. Fourteen-and-a-half–day fetal liver RNA was isolated from μD14 transgenic (tg) animals or nontransgenic (nt) litter mates with the EKLF genotype indicated at the top of each lane. The RNA was analyzed by RNase protection using a human β-globin and a mouse β-major probe. The RNA was also simultaneously analyzed with a GATA-1 probe as a loading control. The position of the protected fragments are indicated to the right of the figure.