Fertilized egg cells trigger, monitor loss of sperm's epigenetic memory

Mouse Zygote | Credit: Image Courtesy
of  Institute of Molecular Biotechnology

"Scientists from the Institute of Molecular Biotechnology (IMBA) in Vienna, Austria, have discovered how an embryo's genomic integrity is safeguarded during the first 24 h after fertilization. Insights into this mechanism have implications for improving in vitro fertilization.

The events triggered when sperm meets an egg are not only life changing for the parents but deeply fascinating from a scientific point of view, too.

The mother of all cells

Following fertilization, DNA from the mother's egg cell and the father's sperm cell constitute the genetic blueprint of the single-cell embryo or zygote. The incoming paternal DNA contains modifications that facilitate an "epigenetic memory" of its sperm state. Proteins provided by the fertilized egg act to largely erase this memory in order to generate a totipotent embryo that can give rise to a whole new individual. 

The mechanisms underlying natural reprogramming to totipotency are remarkably efficient but remain poorly understood. "To put this into perspective, reprogramming to induced pluripotency in cell culture takes several days to weeks whereas reprogramming to totipotency in zygotes occurs in less than 24 h," says Kikuë Tachibana-Konwalski, who devotes her laboratory's research to understanding the molecular secrets of egg cells and zygotes..."

Learn more: 

https://www.sciencedaily.com/releases/2016/12/161201160753.htm