Decoy tricks sperm, prevents fertilization in mice | May 2, 2016 Issue - Vol. 94 Issue 18 | Chemical & Engineering News
Volume 94 Issue 18 | p. 9 | News of The Week
Issue Date: May 2, 2016 | Web Date: April 29, 2016

Decoy tricks sperm, prevents fertilization in mice

Peptide outside of egg cells could lead to new contraceptive strategy
Department: Science & Technology
News Channels: Biological SCENE
Keywords: biotechnology, biochemistry, contraceptives, sperm, fertilization, zona pellucida
[+]Enlarge
Optical (left) and fluorescent (right) micrographs show how human sperm expressing a fluorescent protein bind to agarose beads decorated with the N-terminal fragment of the ZP2 protein.
Credit: J. Cell. Biol.
Micrographs showing human sperm binding to agarose beads.
 
Optical (left) and fluorescent (right) micrographs show how human sperm expressing a fluorescent protein bind to agarose beads decorated with the N-terminal fragment of the ZP2 protein.
Credit: J. Cell. Biol.

A fragment of a protein found outside of egg cells can serve as a decoy for sperm, getting the wiggly sex cells to bind to it instead of an egg, according to a new study (Sci. Transl. Med. 2016, DOI: 10.1126/scitranslmed.aad9946).

This peptide could lead to new strategies for reversible contraceptives or methods to select sperm for in vitro fertilization, the study’s authors write.

In mammals, a spongy matrix consisting of glycoproteins surrounds egg cells. During fertilization, a sperm cell binds to this so-called zona pellucida and then penetrates through it on its way to fuse with the egg. Studies in mice have suggested that the sperm’s specific target in the matrix is a protein called ZP2.

Jurrien Dean of the National Institutes of Health and colleagues tested whether agarose microbeads decorated with the N-terminal fragment of ZP2 could snare sperm in the uterus of mice.

Mice receiving the ZP2 beads had a significantly lower fertilization rate compared with animals receiving naked beads—less than 10% versus almost 85%, respectively.

Dean sees the study as a proof of principle and doesn’t think the peptide beads themselves would be used as contraceptives. One option, he says, could be to add the decoy peptide to spermicidal sponges or vaginal rings that release steroids as a way to increase the efficacy of existing contraceptive methods.

Still, the beads could find other uses. The team determined that sperm captured by the beads were better at binding to and penetrating the zona pellucida than uncaptured sperm, suggesting that the beads could be used to select competent sperm for in vitro fertilization.

 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society
Comments
Michael T Deans MA MSc (May 2, 2016 4:47 PM)
My research, see my book 'Science Uncoiled' or email michaeltdeans@gmail.com for details, suggests zinc nutrition is central to sperm activity (such aphrodisiacs as caviar are Zn-rich).

Leave A Comment

*Required to comment