To further explore the possible relation between Snail and TGF-β2, we examined the status of Snail expression in TGF-β2-null hair buds. As judged by immunohistochemistry, Snail protein was absent from E17.5 skin of TGF-β2-null embryos but not from that of control littermates (Figure 6C). This effect appeared to be exerted at the transcriptional level, since Snail mRNAs were also not found in TGF-β2 null hair buds under conditions in which the signal was readily detected in the hair buds of littermate skin (Figure 6D).