TAp63α induces AP-2γ as an early event in epidermal morphogenesis

Epidermal morphogenesis begins with the commitment of the single-layered surface ectoderm to initiate a stratification program, a process that requires the expression of the transcription factor TAp63α. To determine the molecular mechanism by which TAp63α induces genes associated with the commitment to stratification, such as K14, we have used a combination of in vitro and in vivo approaches. Our initial gene expression profiling studies suggested that TAp63α could regulate one or more AP-2 genes, which have been implicated in development and maintenance of the epidermis. We now demonstrate that TAp63α directly induces AP-2γ expression in embryonic epidermis, when commitment to stratification occurs. Furthermore, we show that, in the absence of AP-2γ, TAp63α fails to induce K14 expression in vitro. Our data identify AP-2γ as the first in vivo target gene of TAp63α, and provide novel insights into the molecular mechanisms associated with early events in epidermal morphogenesis.