Springer Online Journal Archives 1860-2000
Summary Electron microscopic studies of oogenesis in Drosophila melanogaster suggest that the ovarian follicle cells alone are responsible for the secretion of the vitelline membrane and chorion. The synthesis and assembly of the vitelline membrane is a complex process involving several stages of development and different populations of follicle cells. This combined autoradiographic and ultrastructural investigation of vitelline membrane formation has led to the conclusion that the protein component of the vitelline membrane is synthesized in the follicle cells, and that these cells possess a mechanism which directs the polarized synthesis and deposition of vitelline membrane and chorion in response to contact by a specific cell, the oocyte. Under certain aberrant conditions, however, other cell types may serve to induce formation of these membranes. The concept of Drosophila egg coverings as maternal cuticle is also discussed, with regard to the embryonic origin of secreting cells, the requirement for adjacent cells as inducers, and the differences in ultrastructural mechanisms of formation.
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