Postmeiotic unfertilized starfish eggs die by apoptosis

Ozlem Yuce, Kirsten C. Sadler

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish (US)
Pages (from-to)29-44
Number of pages16
JournalDevelopmental Biology
Volume237
Issue number1
DOIs
StatePublished - Sep 1 2001

Keywords

  • Apoptosis
  • Meiotic maturation
  • Oocyte
  • Postmeiotic egg
  • Programmed cell death
  • Protein synthesis
  • Starfish.

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology

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