Kimura Akatsuki, Onami Shuichi
Graduate School of Science and Technology, Keio University, Kohoku, Yokohama, Japan.
Dev Cell. 2005 May;8(5):765-75. doi: 10.1016/j.devcel.2005.03.007.
A male pronucleus migrates toward the center of an egg to reach the female pronucleus for zygote formation. This migration depends on microtubules growing from two centrosomes associated with the male pronucleus. Two mechanisms were previously proposed for this migration: a "pushing mechanism," which uses the pushing force resulting from microtubule polymerization, and a "pulling mechanism," which uses the length-dependent pulling force generated by minus-end-directed motors anchored throughout the cytoplasm. We combined two computer-assisted analyses to examine the relative contribution of these mechanisms to male pronuclear migration. Computer simulation revealed an intrinsic difference in migration behavior of the male pronucleus between the pushing and pulling mechanisms. In vivo measurements using image processing showed that the actual migration behavior in Caenorhabditis elegans confirms the pulling mechanism. A male pronucleus having a single centrosome migrated toward the single aster. We propose that the pulling mechanism is the primary mechanism for male pronuclear migration.
雄性原核向卵子中心移动，以与雌性原核结合形成合子。这种移动依赖于从与雄性原核相关的两个中心体生长出的微管。此前针对这种移动提出了两种机制：一种是“推动机制”，利用微管聚合产生的推力；另一种是“拉动机制”，利用由锚定在整个细胞质中的负端定向马达产生的长度依赖性拉力。我们结合了两种计算机辅助分析方法来研究这些机制对雄性原核移动的相对贡献。计算机模拟揭示了推动机制和拉动机制下雄性原核移动行为的内在差异。利用图像处理进行的体内测量表明，秀丽隐杆线虫中的实际移动行为证实了拉动机制。具有单个中心体的雄性原核向单个星体移动。我们提出拉动机制是雄性原核移动的主要机制。
