University of Hamburg, Department of Developmental Biology, Hamburg, Germany.
Nara Institute of Science and Technology, Graduate School of Science and Technology, Nara, Japan.
J Cell Biol. 2020 Aug 3;219(8). doi: 10.1083/jcb.201907016.
Precise control of cytoskeleton dynamics and its tight coordination with chromosomal events are key to cell division. This is exemplified by formation of the spindle and execution of cytokinesis after nuclear division. Here, we reveal that the central cell cycle regulator CYCLIN DEPENDENT KINASE A;1 (CDKA;1), the Arabidopsis homologue of Cdk1 and Cdk2, partially in conjunction with CYCLIN B3;1 (CYCB3;1), is a key regulator of the microtubule cytoskeleton in meiosis. For full CDKA;1 activity, the function of three redundantly acting CDK-activating kinases (CAKs), CDKD;1, CDKD;2, and CDKD;3, is necessary. Progressive loss of these genes in combination with a weak loss-of-function mutant in CDKA;1 allowed a fine-grained dissection of the requirement of cell-cycle kinase activity for meiosis. Notably, a moderate reduction of CDKA;1 activity converts the simultaneous cytokinesis in Arabidopsis, i.e., one cytokinesis separating all four meiotic products concurrently into two successive cytokineses with cell wall formation after the first and second meiotic division, as found in many monocotyledonous species.
精确控制细胞骨架动态及其与染色体事件的紧密协调是细胞分裂的关键。这可以通过纺锤体的形成和核分裂后胞质分裂的执行来证明。在这里，我们揭示了细胞周期调控因子 CYCLIN DEPENDENT KINASE A;1（CDKA;1），拟南芥同源物 Cdk1 和 Cdk2，部分与 CYCLIN B3;1（CYCB3;1）结合，是减数分裂中微管细胞骨架的关键调节因子。对于完整的 CDKA;1 活性，三个冗余的 CDK-激活激酶（CAKs），CDKD;1、CDKD;2 和 CDKD;3 的功能是必需的。这些基因的逐渐缺失以及 CDKA;1 的弱功能丧失突变，使得对细胞周期激酶活性在减数分裂中的需求进行了精细的剖析。值得注意的是，CDKA;1 活性的适度降低将同时发生的胞质分裂转换为拟南芥，即在第一个和第二个减数分裂后，第一个和第二个减数分裂后形成细胞壁，将所有四个减数分裂产物同时分离成两个连续的胞质分裂，这在许多单子叶植物中都有发现。
