Physical principles of early Drosophila embryogenesis

Abstract During embryonic development each body part is programmed to contain an accurate number and arrangement of cells. This accuracy is achieved through precise integration of cell proliferation with other morphogenetic programs. The overarching goal of this proposal is to reveal the physical principles that ensure accurate control of the cell cycle and morphogenesis during Drosophila embryonic development. We will investigate how the integration of the cell cycle oscillator and cytoskeleton leads to generation of the forces that drive nuclear positioning. We will investigate how cytoplasmic flows are generated by cortical actomyosin contractions to reveal novel and quantitative insights on the physical properties of the cytoplasm. Using several biosensors for the main kinases driving the cell cycle, we will study how these activities are integrated to ensure proper cell cycle control. We will also elucidate how transcriptional regulation of cdc25string ensures precise regulation of the timing of mitosis during gastrulation. Specifically, we will dissect the mechanisms controlling mitotic domains on the dorsal side of the embryos, where they are directly linked to the dynamic of the Decapentaplegic (Dpp) morphogen gradients. Collectively, our experiments will define a quantitative framework elucidating how the cell cycle and morphogenesis are regulated accurately during embryonic development.