生物谷報道：使得哺乳動物精子和卵子能夠相互認識,、然后融合形成一個胚胎的分子事件正在逐漸被揭示出來,。卵細胞膜上的一種分子,，即與Integrin相關的蛋白CD9,，最近被發(fā)現(xiàn)對于精子和卵子的融合來說是非常重要的,，而現(xiàn)在研究人員已在小鼠身上發(fā)現(xiàn)了第一個與精子相關的融合因子,。該分子是免疫球蛋白這一超級蛋白家族的一個成員,，是在NCBI數(shù)據(jù)庫中被發(fā)現(xiàn)的。這種被命名為Izumo（該名稱源自Izumo Taisha,，它是日本的一個與婚姻有關的神社）的蛋白也存在于人精子中,，在那里抗Izumo的抗體阻止精卵融合。隨著與精卵融合有關的更多分子被發(fā)現(xiàn),，研究人員有可能找到受孕和治療不育癥的新方法,。該文發(fā)表在： Nature 434, 234 - 238 (10 March 2005); doi:10.1038/nature03362
The immunoglobulin superfamily protein Izumo is required for sperm to fuse with eggs
NAOKAZU INOUE1, MASAHITO IKAWA2, AYAKO ISOTANI1,3 & MASARU OKABE1,2,3
1 Genome Information Research Center,
2 Research Institute for Microbial Diseases,
3 Faculty of Pharmaceutical Sciences, Osaka University, Yamadaoka 3-1, Suita, Osaka 565-0871, Japan
Correspondence and requests for materials should be addressed to M.O. (e-mail: [email protected]).
Sequences have been deposited with GenBank under accession numbers AB195681 for mouse Izumo, AB195682 for human Izumo and AB195683 for rat Izumo.
Representing the 60 trillion cells that build a human body, a sperm and an egg meet, recognize each other, and fuse to form a new generation of life. The factors involved in this important membrane fusion event, fertilization, have been sought for a long time. Recently, CD9 on the egg membrane was found to be essential for fusion, but sperm-related fusion factors remain unknown. Here, by using a fusion-inhibiting monoclonal antibody and gene cloning, we identify a mouse sperm fusion-related antigen and show that the antigen is a novel immunoglobulin superfamily protein. We have termed the gene Izumo and produced a gene-disrupted mouse line. Izumo-/- mice were healthy but males were sterile. They produced normal-looking sperm that bound to and penetrated the zona pellucida but were incapable of fusing with eggs. Human sperm also contain Izumo and addition of the antibody against human Izumo left the sperm unable to fuse with zona-free hamster eggs.
