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Microtubules Mediate Germ‐nuclear Behavior after Meiosis in Conjugation of Paramecium caudatum
Author(s) -
NAKAJIMA YUKA,
ISHIDA MASAKI,
MIKAMI KAZUYUKI
Publication year - 2002
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2002.tb00344.x
Subject(s) - pronucleus , biology , microtubule , microbiology and biotechnology , meiosis , nucleus , male pronucleus , tubulin , macronucleus , microinjection , paramecium , astral microtubules , genetics , zygote , cell division , spindle apparatus , ciliate , cell , embryo , gene , embryogenesis
. Microtubule dynamics in Paramecium caudatum were investigated with an anti‐α‐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‐α‐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.