To determine whether BMP4 Tg expression in Flk-1+ progenitors restores BMP4 expression suppressed by maternal diabetes, we assessed mRNA and protein levels of BMP4 in embryos with BMP4 Tg expression (embryo genotype: Floxed BMP4; Flk-1-Cre+) or without BMP4 Tg expression (embryo genotype: Floxed BMP4; Flk-1-Cre−) under nondiabetic and diabetic conditions. Here, BMP4 is linked to diabetes mellitus.