Transgenic mice bearing IE3.9int-directed transgenes.

(A) Structure of the GATA-1 gene regulatory region (IE3.9int) cassette. This plasmid contains 3.9 kilobase pairs of sequences 5′ to the IE exon, the IE exon itself, the first intron, and a part of the second exon of the mouse GATA-1gene. The initiation methionine codon in the GATA-1 second exon was deleted and replaced by a unique NotI site for subsequent cloning purpose. Restriction enzyme sites are B,BamHI; E, EcoRI; N, NotI; S,SacI. (B-D) Genomic Southern blot analyses ofIE3.9int-directed transgenic mice. The transgene-specific bands (Tg) and endogenous bands(s) (end) are indicated by arrows on the left of each panel. (E, F) Expression profiles of the IE3.9int-GFPtransgene in bone marrow hematopoietic cells. Strong green fluorescence is observed in both erythroid cells and megakaryocytes (arrow) (E). In FACS analysis, most TER119-positive bone marrow cells are also GFP-positive (F).