Cell polarity and asymmetric division in the peripheral nervous system of Drosophila

During metazoan development, cell fate diversity is generated in part by asymmetric cell divisions, in which mother cells divide to produce two daughter cells with distinct developmental potentials. Adoption of different cell fates often relies on the polarised distribution and unequal segregation of cell-fate determinants. Unequal segregation of cell-fate determinants requires that the mother cell becomes polarised prior to mitosis. In response to this polarisation, cell-fate determinants localise asymmetrically and the mitotic spindle lines up with the pole to which cell-fate determinants accumulate, thereby leading to their unequal partitioning upon cytokinesis. I review here the regulatory mechanisms that establish cell asymmetry and orient this asymmetry relative to the body axis in the sensory organ lineages of Drosophila.