A mouse Shh cDNA was expressed under the control of a 1.6kb fragment of the mouse WAP (whey acidic protein) gene promoter sequence, the second intron of rabbit beta-globin gene and SV40 polyadenylation sequences. Northern blot analysis showed expression of transgenic Shh mRNA in lactating mammary glands from lactation day 1 (L1) primiparous transgenic mice. (J:222841)