Dynamic Change of Cellular Localization of Microtubule-Organizing Center During Conjugation of Ciliate Tetrahymena thermophila.

To obtain a comprehensive picture of microtubule dynamics during conjugation, the mode of sexual reproduction in ciliates, we combined indirect immunofluorescence and three-dimensional imaging using confocal laser-scanning microscope to visualize the cellular localization of DNA, microtubules, and γ-tubulin, the main component of the microtubule-organizing center in mating Tetrahymena cells. As the conjugational stages proceeded, the distribution of γ-tubulin changed drastically and microtubules showed dynamic appearance and disappearance during meiosis, nuclear selection, nuclear exchange, and the development of new macronuclei. This study highlights the involvement of cytoskeletal regulation in the modulation of germline nuclear motilities required for ciliate reproduction.