Yang C-Y, Spielman M, Coles J P, Li Y, Ghelani S, Bourdon V, Brown R C, Lemmon B E, Scott R J, Dickinson H G
Department of Plant Sciences, University of Oxford, South Parks Road, UK.
Plant J. 2003 Apr;34(2):229-40. doi: 10.1046/j.1365-313x.2003.01713.x.
A key step in pollen formation is the segregation of the products of male meiosis into a tetrad of microspores, each of which develops into a pollen grain. Separation of microspores does not occur in tetraspore (tes) mutants of Arabidopsis thaliana, owing to the failure of male meiotic cytokinesis. tes mutants thus generate large 'tetraspores' containing all the products of a single meiosis. Here, we report the positional cloning of the TES locus and details of the role played by the TES product in male cytokinesis. The predicted TES protein includes an N-terminal domain homologous to kinesin motors and a C-terminus with little similarity to other proteins except for a small number of plant kinesins. These include the Arabidopsis HINKEL protein and NACK1 and two from tobacco (Nishihama et al., 2002), which are involved in microtubule organization during mitotic cytokinesis. Immunocytochemistry shows that the characteristic radial arrays of microtubules associated with male meiotic cytokinesis fail to form in tes mutants. The TES protein therefore is likely to function as a microtubule-associated motor, playing a part either in the formation of the radial arrays that establish spore domains following meiosis, or in maintaining their stability.
花粉形成过程中的一个关键步骤是将雄配子减数分裂的产物分离成四分体小孢子，每个小孢子发育成一个花粉粒。由于雄配子减数分裂胞质分裂失败，拟南芥的四孢子（tes）突变体中不会发生小孢子的分离。因此，tes突变体产生包含单次减数分裂所有产物的大“四孢子”。在此，我们报告了TES基因座的定位克隆以及TES产物在雄配子胞质分裂中所起作用的详细情况。预测的TES蛋白包括一个与驱动蛋白马达同源的N端结构域和一个C端，除了少数植物驱动蛋白外，与其他蛋白几乎没有相似性。这些蛋白包括拟南芥的HINKEL蛋白和NACK1以及烟草中的两种蛋白（Nishihama等人，2002年），它们在有丝分裂胞质分裂过程中参与微管组织。免疫细胞化学显示，tes突变体中未能形成与雄配子减数分裂胞质分裂相关的微管特征性径向排列。因此，TES蛋白可能作为一种微管相关马达发挥作用，要么在减数分裂后建立孢子区域的径向排列形成过程中发挥作用，要么在维持其稳定性方面发挥作用。
