Generation of transgenic mice expressing high levels of human embryonic and semi-embryonic hemoglobins.

(A) Structures of human transgenes. Exons are depicted as open boxes, with the positions of the translational initiation and termination codons indicated by tick marks. Globin-gene origins of promoter and enhancer elements (cross-hatched) are also indicated. All transgenes were linked to an identical micro β-LCR cassette (shaded).30 The common name for each transgene and the human globin it expresses are indicated to the left and right of the diagram, respectively. (B) Mating strategy for generating mice expressing human Hb Gower-1 (ζ₂ε₂). Partial globin genotypes of selected mice from 5 generations (F1-F5) are depicted. The strategy facilitates the generation of mice expressing high levels of human Hb ζ₂ε₂ from progenitors expressing hζ or hε globin or containing heterozygous deletion of their endogenous mα or mβ globin genes. A similar strategy was used to generate mice expressing high levels of human Hbs Gower-2 (α₂ε₂) and Portland-2 (ζ₂β₂). m, mouse; h, human; +/+, homozygous; +/−, heterozygous; −/−, nullizygous.