Further studies on the development of the eye of Drosophila melanogaster. I. The ommatidia.

Abstract

AbstractElectron microscope observations on the differentiating Drosophila eye show an extensive proliferation of parallel arrays of microtubules at periods preceding, or coinciding with, alterations in cellular morphology. In the retinular cells they are aligned in the direction of elongation and close to the developing rhabdomeres, forming a cylinder around the central ommatidial axis. At a later stage, in the cone cells, they are aligned in the direction of cellular contraction. Thus as in other developing systems microtubules appear to be directly involved in the morphogenesis of the Drosophila eye. In the retinular cells they gradually disappear during elongation, whereas they persist in the cone cells. The pigment cells contain few of these structures. The distribution of two types of specialised cell attachments, adhering zones and septate desmosomes is discussed in relation to intercellular morphogenesis and communication. The rhabdomeres originate from infoldings of the plasma membrane which later grow out into typical microvilli. Unusul cytoplasmic granules are described in the pigment cells of early pupae.