Int. J. Dev. Biol. 37: 441 - 450 (1993)
© UPV/EHU Press

Cytochalasin-D treatment triggers premature apoptosis of insect ovarian follicle and nurse cells.

I Sauman and S J Berry

Department of Biology, Wesleyan University, Middletown, CT 06457.

ABSTRACT Follicle and nurse cells of developing lepidopteran ovarian follicles are eliminated after oocyte maturation. The process of disintegration of both cell types can be triggered prematurely in the follicle development by in vivo or in vitro treatment with a selective anti-actin agent cytochalasin D. Morphological changes observed in both follicle and nurse cells after cytochalasin D administration at the light and electron microscopy levels reveal all the characteristic morphological markers of a process called apoptosis, or programmed cell death. These changes include detachment of affected cells from basal lamina, loss of microvilli, crowding of structurally intact organelles, condensation of cytoplasm, nuclear shrinkage and fragmentation, and chromatin condensation. Examination of genomic DNA isolated from cytochalasin D affected cells revealed internucleosomal DNA fragmentation--a major biochemical hallmark of apoptosis. Experiments involving administration of actinomycin D or cycloheximide, respectively, indicate that the cell death of follicle and nurse cells triggered by cytochalasin D action does not require new RNA and/or protein synthesis. Possible mechanisms by which cytochalasin D could initiate the lethal biochemical pathway of programmed cell death in both cell types are discussed.