Apoptosis in sea urchin oocytes, eggs, and early embryos

Certain experimental manipulations with sea urchin oocytes, eggs, and early embryos result in induction of cell death. We were interested in whether o r not these cells possessed functional apoptotic machinery, and whether cel lular demise under certain experimental conditions is due to activation of a programmed cell death pathway. Therefore, we evaluated a number of apopto sis assays in sea urchin oocytes, eggs, and early embryos experimentally in duced to apoptose with staurosporine. Our results indicate that these cells each possess and activate necessary apoptotic machinery that leads to char acteristic apoptotic phenotypes. The eggs of this animal have completed mei osis, and are quiescent transcriptionally, translationally, and metabolical ly. Surprisingly, they still undergo apoptosis. The progression through apo ptosis of treated specimens could be followed by morphological changes of t he cells, by chromatin condensation and degradation, and by activation of c aspases. The similarities and differences in the execution of apoptosis bet ween the cell types studied are discussed, Results of this study will be us eful for interpreting experiments in these model systems in which different molecules are targeted for interference and which brings about cell death. Mol. Reprod. Dev. 60: 553-561, 2001. (C) 2001 Wiley-Liss, Inc.