Unexplained infertility may be caused by lack of protein that lets egg and sperm hook up

sperm

You can forget about the birds and the bees. If you really want to learn how babies are made, you need to know about Juno and Izumo.

Fertilization takes place when an egg cell and a sperm cell recognize one another and fuse to form an embryo. But how they recognize each other in order to hook up had remained a mystery.

Researchers said on Wednesday they have identified a protein on the egg cell’s surface that interacts with another protein on the surface of a sperm cell, allowing the two cells to join.

This protein, dubbed Juno in honor of the ancient Roman goddess of fertility and marriage, and its counterpart in sperm,

named Izumo after a Japanese marriage shrine, are essential for reproduction in mammals including people, they said.

This new understanding of the role of these two proteins could help improve the treatment of infertility and guide the development of new contraceptives, the researchers said.

“By identifying this interaction between Juno and Izumo, we now know the identity of the receptor proteins found on the surface of our father’s sperm and our mother’s egg that must interact at the moment at which we were conceived,” said Gavin Wright of the Welcome Trust Sanger Institute in Britain, one of the researchers in the study published in the journal Nature.

The researchers are now screening infertile women to try to determine whether problems with the Juno receptor are to blame.

“It is remarkable that about 20 percent of infertility cases have an unexplained cause,” said Enrica Bianchi of the Sanger Institute, another of the researchers.

“We are now asking whether Juno is involved in these cases of unexplained infertility,” Bianchi added.

Wright said that if defects in the Juno receptor are in fact implicated in human infertility, a simple, non-invasive genetic screening test could be developed to identify affected women.

“This then would allow us to guide the fertility treatment,” Wright said, letting affected women proceed directly to a procedure called intracytoplasmic sperm injection involving direct injection of sperm into an egg obtained from in vitro fertilization.

Japanese researchers identified the sperm cell’s Izumo protein in 2005, but the identity of its counterpart on the egg cell had remained elusive. The Sanger Institute researchers made an artificial version of Izumo to try to find an answer, and found that it interacted with Juno to initiate fertilization.

They then developed mice that lacked Juno. The females of these mice were infertile because their egg cells did not fuse with sperm. The Japanese researchers earlier had shown that male mice lacking the Izumo sperm protein were also infertile.

In the new study, the researchers detected a quick loss of the Juno protein from the egg’s surface after fertilization. They said this may account for how a fertilized egg blocks out additional sperm cells, preventing formation of embryos with more than one sperm cell that would not be viable.

 



News
Entertainment
Sports
Lifestyle
National

California passes 'yes-means-yes' campus sexual assault bill

Californian lawmakers passed a law on Thursday requiring universities to adopt "affirmative consent" language in their definitions of consensual sex, part of a nationwide drive to curb sexual assault on…

National

Syrian refugees top 3 million, half of all…

By Stephanie NebehayGENEVA (Reuters) - Three million Syrian refugees will have registered in neighboring countries as of Friday, but many remain trapped by the advance…

International

North Korean leader's money manager defects in Russia:…

A senior North Korean banking official who managed money for leader Kim Jong Un has defected in Russia and was seeking asylum in a third country, a South Korean newspaper…

Local

MAP: New York City Street Closures August 29,…

The Department of Transportation and NYPD said there may be residual delays near all of the street closures on August 29, 31 and 31. Several streets and avenues will be…

Going Out

'Friends' coffeehouse Central Perk coming to NYC —…

"Friends" is coming back for a one-off special: "The One with the Free Coffee." Warner Bros. is bringing a pop-up replica of Central Perk, the…

Movies

Interview: 'As Above, So Below' directors: 5 ways…

The fraternal directors of the found footage horror "As Above, So Below" dish on the best ways to frighten the bejesus out of audiences.

Movies

Criterion's new Jacques Demy box mixes the light…

Jacques Demy, the most effervescent of French New Wave filmmakers, gets a Criterion box all to himself, with classics like "The Umbrellas of Cherbourg."

Entertainment

Comedian Joan Rivers, 81, rushed to New York…

NEW YORK (Reuters) - Acerbic comedian and fashion critic Joan Rivers was rushed to Mount Sinai Hospital in New York on Thursday after she reportedly…

NFL

3 things we learned in the Giants preseason…

The final score didn’t matter — a 16-13 win by the Giants — but it would’ve been nice to finally see Big Blue’s new-look offense get on track.

NFL

NFL Power Rankings: Seahawks, Broncos, Patriots, 49ers start…

NFL Power Rankings: Seahawks, Broncos, Patriots start at top

U.S. Soccer

5 facts about new England captain Wayne Rooney

Manchester United striker Wayne Rooney was named as the new England captain by coach Roy Hodgson on Thursday.

NFL

Jets vs. Eagles: 3 things to watch

A win on Thursday night at the Eagles would give the Jets a 3-1 record and just their second winning preseason under head coach Rex Ryan.

Style

Trend: White hot on the 2014 Emmy's red…

White was one of the big trends on the Emmy's red carpet.

Food

Recipe: Samuel Adams beer-marinated grilled shrimp

Summer calls for two things: a cold beer and light food. Sam Adams' Latitude 48 IPA fairly bursts with citrus notes, making it an ideal marinade…

Wellbeing

4 healthy ingredient swaps to make your meals…

When it comes to eating well, everyone knows they could be doing better. But cooking in an apartment on a busy schedule is a recipe…

Wellbeing

Heart trumps brain when it comes to movies…

When you need a good cry, do you reach for the movie that’s “based on a true story”? Science says you’re giving your brain far…