Noninvasive visualization of molecular events in the mammalian zygote

Genesis. 2005 Oct;43(2):71-9. doi: 10.1002/gene.20158.


Following fertilization, a number of molecular events are triggered in the mammalian zygote. As biochemical studies using mammalian gametes and zygotes have inherent difficulties, the molecular nature of these processes is currently unclear. We have developed a method to visualize these events. In vitro transcribed mRNAs encoding for proteins fused with green fluorescent protein were microinjected into oocytes or embryos and fluorescence signals were observed. Using this technique we succeeded in obtaining images of the DNA methylation status in living mouse and rabbit embryos. Moreover, time-lapse images were acquired of spindle and nuclear formation during second meiosis and first mitosis. Importantly, the microinjected embryos developed to the normal offspring even after observation, suggesting that the technique is relatively noninvasive. Thus, our method may help elucidate the molecular aspects of fertilization and preimplantation development and, based on the real-time genetic and epigenetic status, could become a tool to select "good quality" embryos before implantation.

Publication types

  • Technical Report

MeSH terms

  • Animals
  • DNA Methylation
  • Embryonic Development*
  • Green Fluorescent Proteins / analysis*
  • Green Fluorescent Proteins / genetics
  • Luminescent Agents / analysis*
  • Mice
  • Microscopy, Fluorescence*
  • Protein Biosynthesis
  • RNA, Messenger / genetics
  • Rabbits
  • Recombinant Fusion Proteins / analysis
  • Recombinant Fusion Proteins / genetics
  • Transfection
  • Zygote / chemistry*
  • Zygote / cytology*
  • Zygote / growth & development


  • Luminescent Agents
  • RNA, Messenger
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins