Germ line Gata1 mutants and transgenic lines used in this study. (A) Schematic representation of the Gata1 germ line mutants and (B) the constructs used for the generation of βLCR and HRD transgenic mice used in this study. Chromosomal localization of mutants and transgenes is indicated on the left; X = X chromosome; A = autosome. References to the original description of mutant or construct are given. The HRD constructs are based on the mouse Gata1 locus. IT and IE: testis- and erythroid-specific first exon, respectively; G1HE = Gata1 hematopoietic element; HS = DNaseI hypersensitive site; SA = splice acceptor; GFP = green fluorescent protein; Neo = neomycin resistance gene. The βLCR constructs are based on the human LCR (βLCR) and human β-globin gene (HBB). Abbreviations used to refer to the germ line mutants and transgenes are shown between brackets.