Intercellular signaling and the polarization of body axes during Drosophila oogenesis.

Abstract

The anterior-posterior and dorsal-ventral axes of the Diosophila egg and embryo are established during oogen­ esis as the egg is being formed. The mechanisms under­ lying this process involve intercellular signaling events, including bidirectional communication between germline and somatic cells, and local cell-cell interactions in the soma. On the molecular level, these interactions ap­ pear to be mediated by a small number of intercellular signaling systems, including the Epidermal growth fac­ tor receptor [Egfr] and Notch systems, that are used mul­ tiple times during oogenesis to trigger different develop­ mental switches. The precisely regulated interplay be­ tween these various signaling systems forms a network of interdependencies that leads to the establishment of both the anterior-posterior and dorsal-ventral polarity in the egg chamber and embryo. Because both the Egfr and Notch signaling systems are widely conserved, the mechanisms involved in the regulation of these pro­ cesses in Drosophila oogenesis may serve as a paradigm for understanding intercellular signaling events in other organisms.