Page URL:

Molecular 'barcode' determines which sperm reaches the egg

14 December 2020
Appeared in BioNews 1076

Protein channels help determine the 'winning sperm' that rises above the other millions to reach the egg, new research has shown.

Sperm tails are lined with protein channels containing pores that allow the entry of calcium, playfully dubbed by researchers as their 'racing stripes'. Researchers at Yale University used a novel 3D molecular imaging technique to visualise this protein within the reproductive tract of female mice after mating, showing which type of protein is essential for sperm to reach the egg.

The team pulished their findings in eLife, stating '[this research] could help identify new targets for contraception and improve current strategies for assisted reproduction'. 

The sperm channels are made up of four protein subunits, CatSper1 to CatSper4, which together ultimately control the motility and navigation of the sperm. They found that the sperm that made it to the oviduct all had intact CatSper1, whereas sperm with broken down CatSper1 were left behind. 

Since CatSper1 is necessary for functional sperm, blocking it may be an effective non-hormonal contraceptive with minimal side effects, claims Dr Jean-Ju Chung, assistant professor of cellular and molecular physiology at Yale School of Medicine and lead author on the study. Alternatively, since mutations have been found in CatSper genes of infertile men, they may become a target for fertility treatments. 

They also found these 'winning sperm' have already lost a cap-like structure called the acrosome in the sperm head, which is proposed to indicate the sperm preparing to fertilise the egg.

The team suggest this new imaging platform will allow scientists to learn more about the fertilisation process in a model more relevant to the true reproductive process than a Petri dish. They say future studies must address what happens once the CatSper1 protein is broken down, and how this impacts the movement and lifespan of sperm. 

3D in situ imaging of the female reproductive tract reveals molecular signatures of fertilising spermatozoa in mice
eLife |  20 October 2020
How to spot winning sperm: Examine their racing stripes
Yale University |  1 December 2020
Molecular signature of fertilising sperm
Front Line Genomics |  9 December 2020
15 February 2021 - by Eleanor Taylor 
Semen samples can now be accurately analysed up to 52 hours after production using a new mail-in sperm testing kit...
11 January 2021 - by Daniel Jacobson 
A molecular mechanism enabling correct sperm motility has been uncovered, shedding light on a key cause of male infertility...
24 August 2020 - by Dr Charlott Repschlager 
Researchers at the University of Eastern Finland found that sperm function better in cervical mucus with less similar immune genes...
10 August 2020 - by Bernie Owusu-Yaw 
Research using high-precision 3D microscopy has overturned 350-year-old observations about how sperm swim...
15 June 2020 - by Ebtehal Moussa 
The fluid that surrounds an egg when it is released acts as a chemical attractant to sperm, but may also select sperm from certain males over others...
to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions

Syndicate this story - click here to enquire about using this story.