Figure 4.

βh0 is activated exclusively during primitive erythropoiesis in embryos with the promoter of Ey deleted. (A) Steady state RT-PCR strategy to detect and quantitate transcription from βh0. PCR primers were perfect matches for βh0 and βh1 cDNA. (asterisk) The amplified region contained one restriction enzyme site in βh0 (BslI) that was not present in βh1 cDNA. Amplified cDNA from e10.5 yolk sacs of wild-type D/S and (B) ΔEyΔβh1/S, (C) ΔEy/S, and (D) Δβh1/S. All samples were digested with BslI. (E) Quantitation of βh0 expression in each mutant genotype comparing the ratio of βh1 (uncut) and βh0 (cut), adjusted for the number of active βh1 alleles. Error bars represent SD of at least 3 embryos of that genotype in a litter.