DISRUPTION OF SCALE DEVELOPMENT BY DELTA-1 MISEXPRESSION

Notch and its ligands are molecules known to be involved in many cell fate decisions, Due to the proposed role of this signaling system in t he choice between feather and smooth skin fate in the embryonic chick, we sought to test whether Notch signaling may also play a role in det ermining scale fate, Notch-1 and -2 Serrate-1 and -2, and Delta-1 are expressed in the scales throughout their development. Misexpression of chick Delta-1 using a replication-competent retrovirus results in reg ions of scale loss. In addition, feather buds are often observed on so me of the scuta scales. These results suggest a model in which Delta c an act as an inhibitor of skin appendage fate as well as a promoter of feather fate. (C) 1998 Academic Press.