Loss of centrioles and polyploidization in follicle cells of Drosophila melanogaster

Abstract

Centrioles of the nurse cells of Drosophila have been shown to move into the oocyte prior to polyploidization of the nurse cells. In order to determine whether or not centriolar loss always occurs in polyploid insect cells, the follicular epithelium of the Drosophila ovary was studied. The DNA content of the cells was determined by cytophotometry of Feulgen-stained squash preparations. The first two endomitotic replications occur at stage 7 and 8. Two additional replications occur prior to stage 11, but the DNA content appears to be under-replicated. Centrioles are found in follicle cells until stage 10 at which time they are no longer present. At the inception of polyploidization the centrioles are no longer closely associated with each other or the nuclear envelope. Instead, they are located adjacent to the plasma membrane at the basal surface. These results closely parallel the previous results found for the nurse cells. Hence, it may be a general observation that centrioles are gradually lost in polyploid insect cells.