Planar cell polarity in the Drosophila eye: Cell fate and organization

Abstract

This chapter focuses on the specific features of planar cell polarity (PCP) establishment, signaling, and cellular read-out in the Drosophila eye (one of several Drosophila tissues with specific advantages for the genetic dissection and analysis of the process). The study of the establishment of PCP in the Drosophila retina serves as a paradigm for PCP establishment in multicellular units. The chapter reviews the molecular aspects of PCP signaling in the fly eye, and compares it to PCP signaling in other fly tissues and in general, to discuss the eye-specific and common read-outs resulting from the interpretation of the initial PCP signaling. The Drosophila eye, like all insect eyes, is a compound eye, containing several hundred ommatidia, each representing a separate unit. Each point in space is perceived by one ommatidium. a whole aspect of Drosophila eye development and patterning relates to the precise organization of the ommatidia with respect to their neighboring ommatidia and their position within the eye. Also, the establishment of this very precise arrangement is mediated by the PCP genes, and it is not only necessary for the proper arrangement of single ommatidia within the eye, but also for the proper arrangement of photoreceptors within each ommatidium itself.