Hprt1^{tm5(Myh7-GFP,Myh6-CFP)Unc}

A targeting vector was designed to insert a 5.5 kb mouse Myh7 (bMHC) promoter driving a nuclear GFP, two copies of chicken beta globin HS4 insulators, a 5.6 kb mouse Myh6 (aMHC) promoter driving a cytoplasmic CFP and the human Hprt promoter (plus exons 1 and 2) upstream of mouse exon 3. CFP is expressed at low levels in the cells of day old mice, but at high levels in virtually all cells by postnatal day 10. GFP expression did not occur in adult cardiac myocytes. (J:139125)