Drosophila embryo polarity

The localisation of bicoid, oskar and gurken mRNAs in the Drosophila oocyte defines the anterior- posterior and dorsal-ventral axes of the embryo. In situ hybridisations to bicoid (top), oskar (middle) and gurken (bottom) mRNAs in stage 10 Drosophila egg chambers. The egg chambers consists of 15 nurse cells and a large oocyte (right), which is surrounded by a layer of somatic follical cells. Bicoid mRNA localises to anterior of the oocyte, directing where head and thorax of embryo develop. Posterior localisation of oskar mRNA directs formation of the pole plasm that contains the abdominal and germline determinants. Gurken is translated on the dorsal side, producing a signalling molecule that causes adjacent follical cells to define the embryo's dorsal-ventral axis. Biomedical Image Awards 2002.