Mice Lacking Two Sperm Serine Proteases, ACR and PRSS21, Are Subfertile, but the Mutant Sperm Are Infertile In Vitro
Mice Lacking Two Sperm Serine Proteases, ACR and PRSS21, Are Subfertile, but the Mutant Sperm Are Infertile In Vitro
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DOI：
10.1095/biolreprod.109.083089
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发表时间：
2010-09-01
影响因子：
3.6
通讯作者：
Baba, Tadashi
中科院分区：
文献类型：
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作者：
Kawano, Natsuko;Kang, Woojin;Baba, Tadashi
尽管精子丝氨酸蛋白酶和蛋白酶体一直被认为在受精过程中起着重要作用，但其分子机制仍存在争议。在这项研究中，我们建立了缺乏两种精子丝氨酸蛋白酶ACR和PRSS21的双基因敲除小鼠，以揭示类胰蛋白酶活性在受精中的功能作用。双基因敲除的雄性小鼠不能生育，可能是由于输卵管壶腹部受精不完全所致。尽管雄性不育，但突变的附睾精子不能在透明带(ZP)表面进行顶体胞吐，也不能穿越ZP，从而导致体外受精失败。双敲除的附睾精子在穿透卵丘基质到达ZP时也存在缺陷。将附睾精子人工注射到野生型小鼠的子宫中，以前用双敲除精子受精的2-细胞胚胎的回收率很低，但有显著意义。突变的附睾精子也能在子宫液存在的情况下体外受精。这些结果表明，ACR和PRSS21的类胰酶活性在精子穿透卵丘基质和卵丘的体外过程中是必不可少的，并提示雌性生殖道对精子功能的丧失具有部分补偿作用。因此，我们得出结论，精子类胰酶活性对于小鼠体内受精仍然重要，但不是必需的。
Although sperm serine protease and proteasome have long been believed to play an important role in the fertilization process, the molecular mechanism is still controversial. In this study, we have produced double-knockout mice lacking two sperm serine proteases, ACR and PRSS21, to uncover the functional role of the trypsinlike activity in fertilization. The double-knockout male mice were subfertile, likely owing to the incompleteness of fertilization in the oviductal ampulla. Despite male subfertility, the mutant epididymal sperm exhibited the inability to undergo acrosomal exocytosis on the zona pellucida (ZP) surface and to traverse the ZP, thus resulting in the failure of fertilization in vitro. The double-knockout epididymal sperm were also defective in penetration through the cumulus matrix to reach the ZP. When epididymal sperm were artificially injected into the uterus of wild-type mice, the 2-cell embryos, which had previously been fertilized by double-knockout sperm, were recovered at a low but significant level. The mutant epididymal sperm were also capable of fertilizing the oocytes in the presence of uterine fluids in vitro. These data demonstrate that the trypsinlike protease activity of ACR and PRSS21 is essential for the process of sperm penetration through the cumulus matrix and ZP in vitro, and suggest that the female reproductive tract partially compensates for the loss of the sperm function. We therefore conclude that the sperm trypsinlike activity is still important but not essential for fertilization in vivo in the mouse.