Egg meets sperm: The female side of the story

October 21, 2010

Researchers at the Swedish medical university Karolinska Institutet have been able to describe the 3D structure of a complete egg receptor that binds sperm at the beginning of fertilization. The results, published in the journal Cell, will lead to better understanding of infertility and may enable entirely new types of contraceptives.

For centuries, the imagination of people has been grasped by the encounter of gametes - egg and sperm-, whose union gives rise to a new individual. At the beginning of conception, sperm binds to proteins in the extracellular coat of the egg, called zona pellucida (ZP). But the molecular details of this fundamental biological event have so far remained obscure.

Luca Jovine's research team at Karolinska Institutet has now managed to determine the three-dimensional structure of the receptor molecule that binds sperm, called ZP3 (see press photos). The detailed structural information, based on data collected at the European Synchrotron Radiation Facility (ESRF), makes it possible to begin exploring at the molecular level how the egg interacts with sperm at fertilization.

The study suggests which parts of the receptor are likely to be directly contacted by sperm, and provides new insights into how the sperm receptor is assembled and secreted from the egg. The findings have important implications for human reproductive medicine, as they may explain how mutations in the sperm receptor gene could cause infertility. The research could also potentially lead to the design of non-hormonal contraceptives specifically targeting egg-sperm interaction.

"The results give a remarkable picture of the female side of fertilization", says Luca Jovine, who has led the study. "But this is, of course, only half of the story. The next step will be to tackle the corresponding molecules on sperm that allow it to bind to the egg."
-end-
The research was performed in collaboration with Prof. Tsukasa Matsuda at Nagoya University, Japan, and Dr. David Flot at the ESRF. It was funded by the Center for Biosciences; the Swedish Research Council; the EU Sixth Framework Programme; the Scandinavia-Japan Sasakawa Foundation; Grant-in-aids from the Japan Society for the Promotion of Science and MEXT; and an EMBO Young Investigator award to Luca Jovine.

Publication: "Insights into Egg Coat Assembly and Egg-Sperm Interaction from the X-Ray Structure of Full-Length ZP3", Ling Han, Magnus Monné, Hiroki Okumura, Thomas Schwend, Amy L. Cherry, David Flot, Tsukasa Matsuda & Luca Jovine, Cell, 21 October 2010.

Download images: http://ki.se/pressroom

For further information, please contact:

Dr Luca Jovine
Center for Biosciences
Department of Biosciences and Nutrition
Tel: +46 (0)8-608 33 01
Mobile: +46 (0)70-149 70 14
E-mail: luca.jovine@ki.se
Lab web page: Jovinelab.org

Press Officer Katarina Sternudd
Tel: +46 (0)8-524 838 95
E-mail: katarina.sternudd@ki.se

Karolinska Institutet is one of the world's leading medical universities. Its mission is to contribute to the improvement of human health through research and education. Karolinska Institutet accounts for over 40 per cent of the medical academic research conducted in Sweden, and offers the country's broadest range of education in medicine and health sciences. Since 1901 the Nobel Assembly at Karolinska Institutet has selected the Nobel laureates in Physiology or Medicine. More information on http://ki.se.

Karolinska Institutet

Related Infertility Articles from Brightsurf:

Discovery of genes involved in infertility
A research group from Kumamoto University, Japan has discovered a gene, 'Meiosin', that acts as the switch to turn on meiosis.

New gene for male infertility discovered
Investigators have found that a genetic rearrangement and variants affecting a gene known as SYCP2 are associated with low sperm count and report the first cases implicating the gene in four men with infertility.

Lack of psychological support for those dealing with infertility in the UK
Psychological support for those dealing with infertility and its treatment is received by only just half of those who want it in the UK - with many left to suffer with anxiety, depression, or suicidal thoughts, according to a new study published in Human Fertility.

Chlamydia in testicular tissue linked to male infertility
The potential impact of undiagnosed sexually transmitted chlamydia infection on men's fertility has been highlighted in a study led by scientists at Queensland University of Technology (QUT), which for the first time found chlamydia in the testicular tissue biopsies of infertile men whose infertility had no identified cause.

Infertility's roots in DNA packaging
Japanese researchers find one cause of infertility is the incomplete development of the proteins packaging DNA in sperm cells.

Infertility is linked to small increased risk of cancer
A study of over 64,000 women of childbearing age in the USA has found that infertility is associated with a higher risk of developing cancer compared to a group of over three million women without fertility problems, although the absolute risk is very low at just 2 percent.

Breakthrough in understanding male infertility
Newcastle University experts have identified the importance of gene, RBMXL2, which is similar to an infertility gene found on the Y chromosome, in regulating the production of fully-functioning sperm.

Duration of infertility in men may affect sperm count
A longer duration of infertility was associated with lower sperm count and other parameters of impaired sperm in a BJU International study of 1644 infertile men.

UCLA research may explain some causes of infertility and miscarriage
A new study in the journal Nature Cell Biology has uncovered information about a key stage that human embryonic cells must pass through just before an embryo implants.

Asthma medication linked to infertility in women
Women with asthma who only use short-acting asthma relievers take longer to become pregnant than other women, according to international research led by the University of Adelaide.

Read More: Infertility News and Infertility Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.