Bioethics News

Latest discovery helps to understand the amazing fertilisation process

The knowledge of the chemical structures that govern the processes associated with fertility — more specifically
with the fertilisation process — opens up new possibilities for intervention, with as yet unknown consequences.

A recent article published in the journal Current Biology(1 – Ver AQUÍ) presents new findings on the mechanism by which the sperm and egg can mutually recognise each other during the fertilisation process, allowing the adhesion and penetration of the sperm though the membrane of the egg, as a preliminary step for the chromosomal crossover of both gametes and the generation of a new human being.

keys1The aforementioned study, conducted by investigators from the Karolinska Institute (Stockholm, Sweden), provides data on the three-dimensional chemical structure of an egg membrane receptor called Juno, improving our understanding of how this receptor interacts with the corresponding sperm membrane protein, in the manner of a lock and key.

The discovery of both egg and sperm “signalling” proteins was published two years ago in the journal Nature,2 in a study that established the relationship between two proteins, named “Izumo1” in the sperm and “Juno” in the egg. The investigators observed that, after the sperm enters the egg — possible only after the interaction of the aforementioned proteins Juno and Izumo1 — the Juno receptor is shed from the egg membrane in a rapid reaction aimed at blocking the entry of any other sperm attempting to fertilise it.

A previous study published in 20073 found that the increased calcium ion concentration in the membrane of the egg plays a crucial role for first and successive cell divisions in the fertilisation process, leading towards embryo development.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.