Simerly C R, Hecht N B, Goldberg E, Schatten G
Department of Zoology, University of Wisconsin, Madison 53706.
Dev Biol. 1993 Aug;158(2):536-48. doi: 10.1006/dbio.1993.1211.
The mechanism of sperm tail incorporation and the fate of the tail during mouse fertilization and early embryogenesis were examined. Time-lapse video microscopy and anti-tubulin immunofluorescence show that the incorporation of the sperm tail, but not the sperm head, is sensitive to cytochalasin B (a microfilament inhibitor). Colcemid, a microtubule inhibitor, does not affect tail incorporation. High-resolution, low-voltage scanning electron microscopy demonstrates that the plasma membrane covering the sperm tail does not appear to fuse with the oocyte membrane during in vitro fertilization in the presence of cytochalasin. In control and colcemid-treated oocytes, the plasma membrane along the sperm tail, which is oriented tangential to the egg surfaces, appears to fuse with the oocyte membrane at multiple sites. An antibody to testicular alpha-tubulin detects sperm-derived, but not egg, microtubules and this has permitted us to trace the behavior and disappearance of the sperm tail during embryogenesis. Conventional and confocal microscopy show that following sperm incorporation, the tail often splays into multiple fibers. At the two-cell stage, the axoneme may be localized in either blastomere or it may be found to run through the midbody between both blastomeres. The tail appears to shorten by the 8-cell stage and is undetectable after the 16-32 cell stage. In morulae, tail fragments have been found in outer cells but not in inner ones, and fragments have not be found in blastocysts. These data suggest that microtubules of sperm and oocytes contain different isotypes of alpha-tubulin, nongenomic sperm-derived components survive at least to the morula stage of mouse development, and egg microfilaments are involved in the incorporation of the sperm tail but not the sperm head, which demonstrates that motility during sperm incorporation is different in mammals when compared to lower vertebrates and invertebrates.
研究了小鼠受精和早期胚胎发育过程中精子尾部的纳入机制及其尾部的命运。延时视频显微镜和抗微管蛋白免疫荧光显示，精子尾部而非精子头部的纳入对细胞松弛素B（一种微丝抑制剂）敏感。秋水仙酰胺，一种微管抑制剂，不影响尾部的纳入。高分辨率、低电压扫描电子显微镜表明，在存在细胞松弛素的体外受精过程中，覆盖精子尾部的质膜似乎不会与卵母细胞膜融合。在对照和秋水仙酰胺处理的卵母细胞中，沿着与卵表面相切的精子尾部的质膜似乎在多个部位与卵母细胞膜融合。一种针对睾丸α-微管蛋白的抗体可检测到精子来源而非卵子来源的微管，这使我们能够追踪胚胎发育过程中精子尾部的行为和消失情况。传统显微镜和共聚焦显微镜显示，精子纳入后，尾部常常会散开成多条纤维。在二细胞阶段，轴丝可能定位于任一卵裂球中，或者可能会发现它穿过两个卵裂球之间的中间体。尾部在8细胞阶段似乎会缩短，在16 - 32细胞阶段后则无法检测到。在桑椹胚中，已在外层细胞中发现尾部片段，但内层细胞中未发现，并且在囊胚中也未发现片段。这些数据表明，精子和卵母细胞的微管含有不同亚型的α-微管蛋白，精子来源的非基因组成分至少存活到小鼠发育的桑椹胚阶段，并且卵微丝参与精子尾部而非精子头部的纳入，这表明与低等脊椎动物和无脊椎动物相比，哺乳动物在精子纳入过程中的运动方式有所不同。
