Artificial Activation of Mammalian Oocytes for Cloning

Present Status and Future Perspectives

Takuya Wakai, Junya Ito, Rafael A. Fissore

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

Since the birth of the first cloned sheep, "Dolly", many studies have reported the successful use of cloning by somatic cell nuclear transfer in other mammalian species. In spite of these successes, the efficiency of this technique is low, with less than 10% of generated embryos resulting in offspring. Factors of genetic, epigenetic, and technical origin seem to affect the efficiency of cloning. Further, because these reconstructed embryos do not have the benefit of being activated by the sperm, egg activation relies on artificial procedures such as those delivered by chemical or physical stimuli. In general, these stimuli aim to replicate either the signal delivered by the sperm, namely, elevations in the intracellular concentration of calcium ion ([Ca2+]i), or the outcome of this signal, inactivation of the M-phase kinases that are responsible for the metaphase II arrest. In mammalian fertilization, the sperm initiates repetitive increases in [Ca2+]i that are also known as oscillations, and experimentally replicating these oscillations has been difficult to accomplish, except in mouse eggs where oscillations can be attained by replacing extracellular CaCl2 with SrCl2. In other mammalian species, in the absence of oscillations, most activation protocols incorporate chemical methods to subdue the activity of the M-phase kinases. Here, we will briefly describe oocyte activation protocols presently in use in different species, highlight some of their advantages and disadvantages, and discuss possible improvements.

Original languageEnglish
Title of host publicationPrinciples of Cloning: Second Edition
PublisherElsevier Inc.
Pages3-10
Number of pages8
ISBN (Print)9780123865410
DOIs
Publication statusPublished - Oct 2013
Externally publishedYes

Fingerprint

Cloning
Oocytes
Spermatozoa
Organism Cloning
Chemical activation
Cell Division
Phosphotransferases
Embryonic Structures
Birth Order
Metaphase
Fertilization
Epigenomics
Eggs
Ovum
Sheep
Ions
Calcium

Keywords

  • Bovine
  • Eggs
  • Humans
  • Kinases
  • Mice
  • Oocytes
  • Parthenogenetic activation
  • PLCzeta
  • Sperm

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Wakai, T., Ito, J., & Fissore, R. A. (2013). Artificial Activation of Mammalian Oocytes for Cloning: Present Status and Future Perspectives. In Principles of Cloning: Second Edition (pp. 3-10). Elsevier Inc.. https://doi.org/10.1016/B978-0-12-386541-0.00001-1

Artificial Activation of Mammalian Oocytes for Cloning : Present Status and Future Perspectives. / Wakai, Takuya; Ito, Junya; Fissore, Rafael A.

Principles of Cloning: Second Edition. Elsevier Inc., 2013. p. 3-10.

Research output: Chapter in Book/Report/Conference proceedingChapter

Wakai, Takuya ; Ito, Junya ; Fissore, Rafael A. / Artificial Activation of Mammalian Oocytes for Cloning : Present Status and Future Perspectives. Principles of Cloning: Second Edition. Elsevier Inc., 2013. pp. 3-10
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