(c) N Martineau
Anne Dell教授と共同研究者のStuart Haslam博士
卵子の膜にある糖の分子SLeXが，卵子と精子をくっつきやすくし，受精に重要な役割を果たしていることが明らかになった。受精の最初の段階では，精子の先端にあるタンパク質が卵子の外膜にある特定の糖と適合する必要があるという。新たな研究で，卵子の外膜に他の糖よりもSLeXが豊富に存在することが確認され，未受精で非生存のヒト卵子の外膜を使った実験で，SLeXの結合を抑制する化学物質で外膜を処理した場合，精子との結合が妨げられることが示された。不妊の原因解明と治療はもとより，避妊薬の開発にも役立つと考えられる。（吉田素子）
Revealed: How Sticky Egg Captures Sperm
Researchers have uncovered exactly how a human egg captures an incoming sperm to begin the fertilisation process, in a new study published this week in the journal Science.
The research identifies the sugar molecule that makes the outer coat of the egg 'sticky', which is vital for enabling the sperm and egg to bind together. Researchers across the world have been trying to understand what performs this task for over thirty years.
The scientists behind this study believe their work could help address some of the previously unexplained causes of human infertility and sub-fertility and be very useful for diagnosing this problem in couples who are unable to have children. It could also provide a new target for the development of natural contraceptive agents.
The international team, from the University of Missouri, the University of Hong Kong, Academia Sinica in Taiwan and Imperial College London, discovered that the sugar chain known as the sialyl-lewis-x sequence (SLeX) is highly abundant on the surface of the human egg. After experimenting with a range of synthesised sugars in the laboratory they went on to show that SLeX specifically binds sperm to an egg, and tested their findings using the outer coats of unfertilised 'non-living' human eggs.
"This exciting research is providing the first insights into the molecular events occurring at the very beginning of human life. The details we've discovered here fill in a huge gap in our knowledge of fertility and we hope they will ultimately help many of those people who currently cannot conceive," said Professor Anne Dell CBE FRS FMedSci from the Department of Life Sciences at Imperial College London, who led the team that discovered the SLeX sugars on the egg surface.
［単語和訳］
Sticky：粘着性のある Egg：卵子 Sperm：精子
Researchers：研究者 uncovered：～を明らかにした incoming：入ってくる fertilisation：受精
sugar：糖 molecule：分子 vital：不可欠な
address：～に取り組む unexplained：解明されていない infertility：不妊 sub-fertility：生殖能力低下 diagnosing：～を診断すること contraceptive agents：避妊薬
sugar chain：糖鎖 sialyl-lewis-x：シアリルルイスx（糖鎖の名称） sequence：配列 abundant：豊富にある a range of ：さまざまな synthesised：合成した laboratory：研究室 went on to：次に～することに取り掛かった specifically：特に unfertilised：未受精の non-living：非生存の
insights：知見 fill in a gap in：～を補足する fertility：受精能 ultimately：最終的に currently：現在 conceive：妊娠する CBE：大英勲章第3位 FRS：王立学会特別研究員 FMedSci：Fellow of the United Kingdom Academy of Medical Sciencesの略 Life Sciences：生命科学
