Takayama Jun, Onami Shuichi
Laboratory for Developmental Dynamics, RIKEN Quantitative Biology Center, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
Laboratory for Developmental Dynamics, RIKEN Quantitative Biology Center, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
Cell Rep. 2016 Apr 19;15(3):625-637. doi: 10.1016/j.celrep.2016.03.040. Epub 2016 Apr 7.
Sperm induce Ca(2+) waves in the fertilized egg by introducing soluble factors or by surface interactions, which activate egg Ca(2+) channels. Involvement of sperm Ca(2+) channels is predicted by the conduit model; however, this model has not been validated. In Caenorhabditis elegans, the sperm-specific TRP family Ca(2+) channel TRP-3 mediates sperm-oocyte fusion. Here, using high-speed in vivo imaging and image analyses, we show that sperm induce an immediate local Ca(2+) rise followed by a Ca(2+) wave in fertilized C. elegans oocytes. Oocytes fertilized by rare trp-3 escaper sperm showed a lack of local rise and a delay in onset of the Ca(2+) wave. Sperm Ca(2+) imaging suggests that the local rise is not due to the bolus introduction of stored Ca(2+). These results suggest that, along with its primary function in sperm-oocyte fusion, TRP-3 induces Ca(2+) waves in fertilized oocytes, consistent with the conduit model.
精子通过引入可溶性因子或通过表面相互作用在受精卵中诱导钙（Ca(2+)）波，这会激活卵子的钙（Ca(2+)）通道。导管模型预测精子钙（Ca(2+)）通道参与其中；然而，该模型尚未得到验证。在秀丽隐杆线虫中，精子特异性瞬时受体电位（TRP）家族钙（Ca(2+)）通道TRP-3介导精子-卵母细胞融合。在此，我们使用高速体内成像和图像分析表明，精子在受精的秀丽隐杆线虫卵母细胞中诱导立即出现局部钙（Ca(2+)）升高，随后是钙（Ca(2+)）波。由罕见的trp-3逃逸精子受精的卵母细胞显示缺乏局部升高且钙（Ca(2+)）波起始延迟。精子钙（Ca(2+)）成像表明局部升高并非由于储存钙（Ca(2+)）的大量引入。这些结果表明，除了其在精子-卵母细胞融合中的主要功能外，TRP-3还在受精卵母细胞中诱导钙（Ca(2+)）波，这与导管模型一致。
