A construct was generated by inserting an expression cassette with a floxed Renilla GFP cDNA and mouse polyA, followed by the full length murine Bmp4 cDNA, into an expression vector containing the cytomegalovirus enhancer/mouse beta-actin promoter and mouse beta-globin genomic DNA. This transgenic vector was injected into pronuclei of C57BL/6J oocytes. Lines 1 and 5 were established.