Nakajima Yuka, Ishida Masaki, Mikami Kazuyuki
Environmental Education Center, Miyagi University of Education, Sendai, Japan.
J Eukaryot Microbiol. 2002 Jan-Feb;49(1):74-81. doi: 10.1111/j.1550-7408.2002.tb00344.x.
Microtubule dynamics in Paramecium caudatum were investigated with an anti-alpha-tubulin antibody and a microinjection technique to determine the function of microtubules on micronuclear behavior during conjugation. After meiosis, all four haploid micronuclei were connected by microtubular filaments to the paroral region and moved close to this region. This nuclear movement was micronucleus-specific, because some small macronuclear fragments transplanted from exconjugants never moved to the region. Only one of the four germ nuclei moved into the paroral cone and was covered by microtubule assembly (the so-called first assembly of microtubules, AM-I). This nucleus survived there, while the other three not in this region degenerated. The movement of germ nucleus was inhibited by the injection of the anti-alpha-tubulin antibody. The surviving germ nucleus divided once and produced a migratory pronucleus and a stationary pronucleus. Prior to the reciprocal exchange of the migratory nuclei, microtubules assembled around the migratory pronuclei again (the so-called second assembly of microtubules, AM-II). Then, the migratory pronucleus moved into the partner cell and fused with the stationary pronucleus. Thus, microtubules appear to be indispensable for nuclear behavior: they enable migration of postmeiotic nuclei to the paroral region and they permit the survival of the nucleus at the paroral cone.
利用抗α - 微管蛋白抗体和显微注射技术研究了尾草履虫的微管动力学，以确定微管在接合过程中对小核行为的作用。减数分裂后，所有四个单倍体小核通过微管丝连接到口旁区并移近该区域。这种核运动是小核特异性的，因为从接合后细胞移植的一些大核小片段从未移至该区域。四个生殖核中只有一个移入口旁锥并被微管组装所覆盖（所谓的微管第一次组装，AM - I）。这个核在那里存活下来，而其他三个不在该区域的核则退化。通过注射抗α - 微管蛋白抗体可抑制生殖核的运动。存活的生殖核分裂一次，产生一个迁移性原核和一个静止性原核。在迁移性核相互交换之前，微管再次围绕迁移性原核组装（所谓的微管第二次组装，AM - II）。然后，迁移性原核移入伴侣细胞并与静止性原核融合。因此，微管似乎对核行为是不可或缺的：它们使减数分裂后的核能够迁移到口旁区，并使核在口旁锥处存活。
