The Oocyte-to-Embryo Transition

  • Scott Robertson
  • Rueyling Lin
Part of the Advances in Experimental Medicine and Biology book series (volume 757)


The oocyte-to-embryo transition refers to the process whereby a fully grown, relatively quiescent oocyte undergoes maturation, fertilization, and is converted into a developmentally active, mitotically dividing embryo, arguably one of the most dramatic transitions in biology. This transition occurs very rapidly in Caenorhabditis elegans, with fertilization of a new oocyte occurring every 23 min and the first mitotic division occurring 45 min later. Molecular events regulating this transition must be very precisely timed. This chapter reviews our current understanding of the coordinated temporal regulation of different events during this transition. We divide the oocyte-to-embryo transition into a number of component processes, which are coordinated primarily through the MBK-2 kinase, whose activation is intimately tied to completion of meiosis, and the OMA-1/OMA-2 proteins, whose expression and functions span multiple processes during this transition. The oocyte-to-embryo transition occurs in the absence of de novo transcription, and all the factors required for the process, whether mRNA or protein, are already present within the oocyte. Therefore, all regulation of this transition is posttranscriptional. The combination of asymmetric partitioning of maternal factors, protein modification-mediated functional switching, protein degradation, and highly regulated translational repression ensure a smooth oocyte-to-embryo transition. We will highlight protein degradation and translational repression, two posttranscriptional processes which play particularly critical roles in this transition.


Oocyte maturation Oocyte-to-embryo transition OMA-1 MBK-2 Asymmetric partitioning Protein degradation Translational repression ZIF-1 3′UTR RNA binding 



Work conducted in the authors’ laboratory was supported by NIH grants HD37933 and GM84198.


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© Springer Science+Business Media New York 2013

Authors and Affiliations

  1. 1.Department of Molecular BiologyUniversity of Texas Southwestern Medical CenterDallasUSA

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