Right time, right place: the temporal regulation of developmental gene expression.

Many studies have focused on defining the critical transcription factors that specify tissue morphogenesis and differentiation. Our understanding of how these spatial regulators are deployed in the proper temporal order, however, has remained less clear. In this issue of Genes & Development, Uyehara and colleagues (pp. 862-875) provide new insights into the mechanisms by which temporal and spatial regulators are coordinated to control Drosophila wing development during metamorphosis.