Plümper E, Freiburg M, Heckmann K
Institut für Allgemeine Zoologie und Genetik, Universität Münster, Germany.
Exp Cell Res. 1995 Apr;217(2):490-6. doi: 10.1006/excr.1995.1114.
Pair formation in the hypotrichous ciliate Euplotes octocarinatus is a poorly understood phenomenon. In order to obtain information about the molecules involved in this process, we compared ciliary and cell body-associated glycoconjugates of non-mating-competent, mating-competent, and conjugating cells. Detection of glycoconjugates was carried out on Western blots by immunostaining of oxidized, digoxigenin-labeled carbohydrate moieties. Using this method, in both of two complementary mating types a 130-kDa glycoprotein was identified, which appeared on cilia during acquisition of mating competence and was reduced during cell pairing. This suggests an active role of this glycoprotein in ciliary adhesion during pair formation. Additionally, in both of the two mating types a cell body-associated 135-kDa glycoprotein was detected, which is present in non-mating-competent cells as well as in mating-competent cells, but is strongly reduced in conjugating cells. In contrast to the ciliary 130-kDa glycoprotein, the cell body-associated 135-kDa glycoprotein is not surface-exposed [8]. We therefore propose that the cell body-associated glycoprotein is either involved in the preparation for cell fusion or meiosis or that it serves as a cytoplasmic pool for the ciliary 130-kDa glycoprotein.
八肋游仆虫这种腹毛目纤毛虫的配对形成是一种了解甚少的现象。为了获取有关参与此过程的分子的信息，我们比较了无交配能力、有交配能力和正在接合的细胞的纤毛及与细胞体相关的糖缀合物。通过对氧化的、地高辛标记的碳水化合物部分进行免疫染色，在蛋白质免疫印迹法上检测糖缀合物。使用这种方法，在两种互补交配类型中均鉴定出一种130 kDa的糖蛋白，它在获得交配能力期间出现在纤毛上，并在细胞配对期间减少。这表明这种糖蛋白在配对形成过程中的纤毛黏附中发挥着积极作用。此外，在两种交配类型中均检测到一种与细胞体相关的135 kDa糖蛋白，它存在于无交配能力的细胞以及有交配能力的细胞中，但在正在接合的细胞中含量大幅减少。与纤毛的130 kDa糖蛋白不同，与细胞体相关的135 kDa糖蛋白不暴露于表面[8]。因此，我们提出与细胞体相关的糖蛋白要么参与细胞融合或减数分裂的准备过程，要么作为纤毛130 kDa糖蛋白的细胞质储备库。
