Barraud-Lange Virginie, Naud-Barriant Nathalie, Bomsel Morgane, Wolf Jean-Philippe, Ziyyat Ahmed
Université Paris 13, UFR SMBH, Laboratoire de Biologie de la Reproduction, and AP-HP Hôpital Jean Verdier, Bondy, France.
FASEB J. 2007 Nov;21(13):3446-9. doi: 10.1096/fj.06-8035hyp. Epub 2007 Jun 15.
Several families of molecules are implicated in the membrane fusion process between sperm and oocyte. Among these, CD9 tetraspanin, a membrane-organizing molecule, plays a crucial role, since the fertilizing ability of CD9-/- oocytes is dramatically impaired. CD9 controls alpha6-beta1 integrin relocation involved in the membrane reorganization that occurs on oocyte fertilization but is not expressed on sperm. We report here that, together with several other proteins, the CD9 tetraspanin is transferred from the oocyte to the fertilizing spermatozoa present in the perivitelline space before fertilization. Transfer of CD9 from oocyte to sperm from CD9-/- male mice still occurs. CD9 acquisition by sperm results from a transfer of membrane fragments from the plasma membrane of the oocyte, in a process similar to trogocytosis, the recently described mechanism of intercellular exchange of membrane patches. Acquisition of CD9 by the sperm may be crucial for the membrane reorganization in sperm required for fusion with the oocyte, a process that is similar to the role CD9 plays in oocyte membrane reorganization.
有几个分子家族参与精子与卵母细胞之间的膜融合过程。其中，CD9四跨膜蛋白作为一种膜组织分子发挥着关键作用，因为CD9基因敲除的卵母细胞受精能力显著受损。CD9控制着α6-β1整合素的重新定位，这一过程参与卵母细胞受精时发生的膜重组，但在精子上不表达。我们在此报告，在受精前，CD9四跨膜蛋白与其他几种蛋白质一起，从卵母细胞转移到卵周隙中的受精精子上。CD9从CD9基因敲除雄性小鼠的卵母细胞向精子的转移仍然会发生。精子获取CD9是由于卵母细胞质膜的膜片段转移，这一过程类似于噬菌作用，即最近描述的细胞间膜片交换机制。精子获取CD9可能对精子与卵母细胞融合所需的膜重组至关重要，这一过程类似于CD9在卵母细胞膜重组中所起的作用。
