Egg activation events are regulated by the duration of a sustained [Ca 2+]cyt signal in the mouse

Jean Pierre Ozil*, Styliani Markoulaki, Szabolcs Toth, Sara Matson, Bernadette Banrezes, Jason G. Knott, Richard M. Schultz, Daniel Huneau, Tom Ducibella

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

146 Scopus citations

Abstract

Although the dynamics of oscillations of cytosolic Ca2+ concentration ([Ca2+]cyt) play important roles in early mammalian development, the impact of the duration when [Ca2+] cyt is elevated is not known. To determine the sensitivity of fertilization-associated responses [i.e., cortical granule exocytosis, resumption of the cell cycle, Ca2+/calmodulin-dependent protein kinase II (CaMKII) activity, recruitment of maternal mRNAs] and developmental competence of the parthenotes to the duration of a [Ca2+] cyt transient, unfertilized mouse eggs were subjected to a prolonged [Ca2+]cyt change for 15, 25, or 50 min by means of repetitive Ca2+ electropermeabilization at 2-min intervals. The initiation and completion of fertilization-associated responses are correlated with the duration of time in which the [Ca2+]cyt is elevated, with the exception that autonomous CaMKII activity is down-regulated with prolonged elevated [Ca2+]cyt. Activated eggs from 25- or 50-min treatments readily develop to the blastocyst stage with no sign of apoptosis or necrosis and some implant. Ca2+ influx into unfertilized eggs causes neither Ca2+ release from intracellular stores nor rapid removal of cytosolic Ca2+. Thus, the total Ca2+ signal input appears to be an important regulatory parameter that ensures completion of fertilization-associated events and oocytes have a surprising degree of tolerance for a prolonged change in [Ca2+]cyt.

Original languageEnglish (US)
Pages (from-to)39-54
Number of pages16
JournalDevelopmental Biology
Volume282
Issue number1
DOIs
StatePublished - Jun 1 2005

Keywords

  • Ca signal duration
  • CaMKII
  • Egg activation
  • Electropermeabilization
  • Phosphoinositide
  • Preimplantation mouse embryo

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology
  • Developmental Biology

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