Chapter 6 Contractile and Cytoskeletal Proteins in Drosophila Embryogenesis

In Drosophila and other organisms, force production and transmission for cell shape changes during development; such movements are an integral part of homeostasis and development. A molecular description of how forces are produced, by components of the cytoskeleton, and then transmitted to membranes are discussed in the chapter. This chapter generates a complete catalog of the molecular players that contribute to cell shape changes and investigates the signals that effect such changes at precise times and locations in a developing embryo. Drosophila offers new hope for solutions to these problems, as a consequence of powerful genetic and molecular genetic approaches that are uniquely developed in this organism among metazoans. The chapter discusses the progress in examining the primary structure of a cellular motor protein, conventional, nonmuscle myosin, and the examination of the role it plays in cell shape change in Drosophila and explains the analysis of other key components of the cytoskeleton and membrane skeleton, the spectrins, and a description of a new isoform of β-spectrin, βH. In Drosophila, spectrin polypeptides were first identified in an enriched fraction of high molecular-weight actin-binding proteins. By electron microscopy of platinum-shadowed specimens, a species in this heterogeneous fraction were found to be molecules, with amorphology, comparable to vertebrate spectrins. They appear to contribute to an anastomosing meshwork that provides mechanical support for the plasma membrane. Actin, myosin, and spectrins are key components of the membrane skeleton and cytoskeleton. This chapter discusses the movements of early embryogenesis— namely, pole cell formation, cellularization, and gastrulation —and cell shape change that requires remodeling of the actin cytoskeleton, nonmuscle myosins are also discussed in the chapter. © 1991, Elsevier Inc. All rights reserved.

Duke Scholars

Author Daniel P. Kiehart Biology