The cre recombinase cDNA was combined with a 5.5kb mouse Nphs1 promoter fragment and intron of the rabbit beta-globin gene. The construct was injected into fertilized eggs from (C57BL/6 x DBA/2) x C57BL/6N mice. Cre mRNA was detected in the kidney by Northern blot in five lines, and Cre protein was detected in podocytes by immunohistochemistry in four lines. Line 10 was established by backcrossing to C57BL/6 mice.