FGF Signaling Is Required for Initiation of Feather Placode Development

The study concluded that FGF signaling was essential for the initiation of feather placode development. This was demonstrated through experiments where ppf explants were cultured with 25 μM Su5402, an inhibitor of FGF signaling, which resulted in the absence of detectable di-phosphorylation of ERK1 and ERK2. This indicated that the concentration of Su5402 used was sufficient to block FGF signaling in vitro, thereby confirming the necessity of FGF signaling in the early stages of feather development.