Featured Research

from universities, journals, and other organizations

Sperm meets egg: Protein essential for fertilization discovered

Date:
April 16, 2014
Source:
Wellcome Trust Sanger Institute
Summary:
Interacting proteins on the surface of the sperm and the egg have been discovered by researchers. These are essential to begin mammalian life. These proteins, which allow the sperm and egg to recognize one another, offer new paths towards improved fertility treatments and the development of new contraceptives.

In-vitro fertilization assay.
Credit: Image courtesy of Wellcome Trust Sanger Institute

Researchers at the Wellcome Trust Sanger Institute have discovered interacting proteins on the surface of the sperm and the egg essential to begin mammalian life. These proteins, which allow the sperm and egg to recognize one another, offer new paths towards improved fertility treatments and the development of new contraceptives.

Fertilization occurs when an egg and a sperm recognize each other and fuse together to form an embryo. The Izumo protein displayed on the sperm that recognizes the egg was identified in 2005 by Japanese researchers who named it Izumo, after a Japanese marriage shrine, but its mate on the egg has remained a mystery. That is until now.

The team identified a single protein that paired with Izumo and is necessary for fertilization. The protein is named Juno after the Roman Goddess of fertility and marriage.

"We have solved a long-standing mystery in biology by identifying the molecules displayed on all sperm and egg that must bind each other at the moment we were conceived," says Dr Gavin Wright, senior author from the Sanger Institute. "Without this essential interaction, fertilization just cannot happen. We may be able to use this discovery to improve fertility treatments and develop new contraceptives."

The scientists created an artificial version of the Izumo protein and used this to identify binding partners on the surface of the egg. Using this approach, they discovered that Izumo on the sperm interacted with Juno on the surface of the egg to initiate fertilization.

The team developed mice that lacked the Juno protein on the surface of their eggs. These mice were infertile and their eggs did not fuse with normal sperm, highlighting that the Juno protein is essential for fertility in female mice. In the same way, male mice lacking the Izumo protein are also infertile, highlighting its essential role in male fertility.

"The Izumo-Juno pairing is the first known essential interaction for sperm-egg recognition in any organism," says Dr Enrica Bianchi, first author from the Wellcome Trust Sanger Institute. "The binding of the two proteins is very weak, which probably explains why this has remained a mystery until now.

"Previous work in the laboratory led us to expect the interaction to be weak, and this then guided the design of our experiments, and, after a lot of effort, it finally worked."

The team found that after the initial fertilization step, there is a sudden loss of the Juno protein from the surface of the egg, becoming virtually undetectable after just 40 minutes. This may explain why the egg, once fertilized by the first sperm cell, shuts down its ability to recognize further sperm. This prevents the formation of embryos with more than one sperm cell that would otherwise have too many chromosomes and die.

The team is now screening infertile women to understand whether defects in the Juno receptor are a cause of infertility. If it is, then a simple genetic screening test could help inform the appropriate treatment for women struggling to conceive naturally by reducing the expense and stress often involved in assisted fertility treatments.


Story Source:

The above story is based on materials provided by Wellcome Trust Sanger Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. Enrica Bianchi, Brendan Doe, David Goulding, Gavin J. Wright. Juno is the egg Izumo receptor and is essential for mammalian fertilization. Nature, 2014; DOI: 10.1038/nature13203

Cite This Page:

Wellcome Trust Sanger Institute. "Sperm meets egg: Protein essential for fertilization discovered." ScienceDaily. ScienceDaily, 16 April 2014. <www.sciencedaily.com/releases/2014/04/140416133253.htm>.
Wellcome Trust Sanger Institute. (2014, April 16). Sperm meets egg: Protein essential for fertilization discovered. ScienceDaily. Retrieved July 21, 2014 from www.sciencedaily.com/releases/2014/04/140416133253.htm
Wellcome Trust Sanger Institute. "Sperm meets egg: Protein essential for fertilization discovered." ScienceDaily. www.sciencedaily.com/releases/2014/04/140416133253.htm (accessed July 21, 2014).

Share This




More Health & Medicine News

Monday, July 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com
Tooth Plaque Provides Insight Into Diets Of Ancient People

Tooth Plaque Provides Insight Into Diets Of Ancient People

Newsy (July 19, 2014) Research on plaque from ancient teeth shows that our prehistoric ancestor's had a detailed understanding of plants long before developing agriculture. Video provided by Newsy
Powered by NewsLook.com
Contaminated Water Kills 3 Babies in South African Town

Contaminated Water Kills 3 Babies in South African Town

AFP (July 18, 2014) Contaminated water in South Africa's northwestern town of Bloemhof kills three babies and hospitalises over 500 people. The incident highlights growing fears over water safety in South Africa. Duration: 02:22 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins