TY - JOUR
T1 - Postmeiotic unfertilized starfish eggs die by apoptosis
AU - Yuce, Ozlem
AU - Sadler, Kirsten C.
N1 - Funding Information:
We thank the Bosphorus University Diving Club, who tirelessly collected the animals used in our studies, Fisun Hamaratog˘lu who contributed to several of the experiments, and André Picard, who provided encouragement, valuable discussions, and participation in the A. aranciacus experiments. We also wish to thank Can Akc¸ali for discussions and annexin V assay, members of the Sadler lab for enthusiasm and support, and Kuyas¸ Bug˘ra and Ahmet Koman for critically reading this manuscript. This work was supported by grants from the Bosphorus University Research Fund and The Turkish Scientific and Technical Research Counsel (TU˝ BITAK 100T049) (to K.C.S.).
PY - 2001/9/1
Y1 - 2001/9/1
N2 - Fertilization of starfish eggs during meiosis results in rapid progression to embryogenesis as soon as meiosis II is completed. Unfertilized eggs complete meiosis and arrest in postmeiotic interphase for an, until now, indeterminate time. If they remain unfertilized, the mature postmeiotic eggs ultimately die. The aim of this study is to characterize the mechanism of death in postmeiotic unfertilized starfish eggs. We report that, in two species of starfish, in the absence of fertilization, postmeiotic interphase arrest persists for 16-20 h, after which time the cells synchronously and rapidly die. Dying eggs extrude membrane blebs, undergo cytoplasmic contraction and darkening, and fragment into vesicles in a manner reminiscent of apoptotic cells. The DNA of dying eggs is condensed, fragmented, and labeled by the TUNEL assay. Taken together, these data suggest that the default fate of postmeiotic starfish eggs, like their mammalian counterparts, is death by apoptosis. We further report that the onset and execution of apoptosis in this system is dependent on ongoing protein synthesis and is inhibited by a rise in intracellular Ca2+, an essential component of the fertilization signaling pathway. We propose starfish eggs as a useful model to study developmentally regulated apoptosis.
AB - Fertilization of starfish eggs during meiosis results in rapid progression to embryogenesis as soon as meiosis II is completed. Unfertilized eggs complete meiosis and arrest in postmeiotic interphase for an, until now, indeterminate time. If they remain unfertilized, the mature postmeiotic eggs ultimately die. The aim of this study is to characterize the mechanism of death in postmeiotic unfertilized starfish eggs. We report that, in two species of starfish, in the absence of fertilization, postmeiotic interphase arrest persists for 16-20 h, after which time the cells synchronously and rapidly die. Dying eggs extrude membrane blebs, undergo cytoplasmic contraction and darkening, and fragment into vesicles in a manner reminiscent of apoptotic cells. The DNA of dying eggs is condensed, fragmented, and labeled by the TUNEL assay. Taken together, these data suggest that the default fate of postmeiotic starfish eggs, like their mammalian counterparts, is death by apoptosis. We further report that the onset and execution of apoptosis in this system is dependent on ongoing protein synthesis and is inhibited by a rise in intracellular Ca2+, an essential component of the fertilization signaling pathway. We propose starfish eggs as a useful model to study developmentally regulated apoptosis.
KW - Apoptosis
KW - Meiotic maturation
KW - Oocyte
KW - Postmeiotic egg
KW - Programmed cell death
KW - Protein synthesis
KW - Starfish.
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U2 - 10.1006/dbio.2001.0361
DO - 10.1006/dbio.2001.0361
M3 - Article
C2 - 11518503
AN - SCOPUS:0035448516
SN - 0012-1606
VL - 237
SP - 29
EP - 44
JO - Developmental Biology
JF - Developmental Biology
IS - 1
ER -