Increased sensitivity and clustering of elementary Ca 2+ release events during oocyte maturation

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

The universal signal for egg activation at fertilization is a rise in cytoplasmic Ca 2+ with defined spatial and temporal kinetics. Mammalian and amphibian eggs acquire the ability to produce such Ca 2+ signals during a maturation period that precedes fertilization and encompasses resumption of meiosis and progression to metaphase II. In Xenopus, immature oocytes produce fast, saltatory Ca 2+ waves that can be oscillatory in nature in response to IP 3. In contrast, mature eggs produce a single continuous, sweeping Ca 2+ wave in response to IP 3 or sperm fusion. The mechanisms mediating the differentiation of Ca 2+ signaling during oocyte maturation are not well understood. Here, I characterized elementary Ca 2+ release events (Ca 2+ puffs) in oocytes and eggs and show that the sensitivity of IP 3-dependent Ca 2+ release is greatly enhanced during oocyte maturation. Furthermore, Ca 2+ puffs in eggs have a larger spatial fingerprint, yet are short lived compared to oocyte puffs. Most interestingly, Ca 2+ puffs cluster during oocyte maturation resulting in a continuum of Ca 2+ release sites over space in eggs. These changes in the spatial distribution of elementary Ca 2+ release events during oocyte maturation explain the continuous nature and slower speed of the fertilization Ca 2+ wave.

Original languageEnglish
Pages (from-to)170-182
Number of pages13
JournalDevelopmental Biology
Volume275
Issue number1
DOIs
Publication statusPublished - 1 Nov 2004
Externally publishedYes

Fingerprint

Oocytes
Cluster Analysis
Eggs
Fertilization
Meiosis
Dermatoglyphics
Amphibians
Metaphase
Xenopus
Ovum
Spermatozoa

Keywords

  • Ca imaging
  • Ca puffs
  • Ca signaling
  • Ca waves
  • Elementary Ca release
  • Fertilization
  • IP3-dependent Ca release
  • Meiosis
  • Oocyte maturation
  • Xenopus

ASJC Scopus subject areas

  • Developmental Biology

Cite this

Increased sensitivity and clustering of elementary Ca 2+ release events during oocyte maturation. / Machaca, Khaled.

In: Developmental Biology, Vol. 275, No. 1, 01.11.2004, p. 170-182.

Research output: Contribution to journalArticle

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