Yamashita Akira, Yamamoto Masayuki
Molecular Genetics Research Laboratory, University of Tokyo, Japan.
Genetics. 2006 Jul;173(3):1187-96. doi: 10.1534/genetics.105.050062. Epub 2006 Apr 19.
During meiotic prophase in the fission yeast Schizosaccharomyces pombe, the nucleus oscillates between the two ends of a cell. This oscillatory nuclear movement is important to promote accurate pairing of homologous chromosomes and requires cytoplasmic dynein. Dynein accumulates at the points where microtubule plus ends contact the cell cortex and generate a force to drive nuclear oscillation. However, it remains poorly understood how dynein associates with the cell cortex. Here we show that S. pombe Num1p functions as a cortical-anchoring factor for dynein. Num1p is expressed in a meiosis-specific manner and localized to the cell cortex through its C-terminal PH domain. The num1 deletion mutant shows microtubule dynamics comparable to that in the wild type. However, it lacks cortical accumulation of dynein and is defective in the nuclear oscillation as is the case for the dynein mutant. We also show that Num1p can recruit dynein independently of the CLIP-170 homolog Tip1p.
在裂殖酵母粟酒裂殖酵母减数分裂前期，细胞核在细胞的两端之间振荡。这种振荡性核运动对于促进同源染色体的准确配对很重要，并且需要细胞质动力蛋白。动力蛋白聚集在微管正端与细胞皮层接触的点上，并产生驱动力以驱动核振荡。然而，动力蛋白如何与细胞皮层结合仍知之甚少。在这里，我们表明粟酒裂殖酵母Num1p作为动力蛋白的皮层锚定因子发挥作用。Num1p以减数分裂特异性方式表达，并通过其C端PH结构域定位于细胞皮层。num1缺失突变体显示出与野生型相当的微管动力学。然而，它缺乏动力蛋白在皮层的积累，并且在核振荡方面存在缺陷，就像动力蛋白突变体一样。我们还表明，Num1p可以独立于CLIP-170同源物Tip1p招募动力蛋白。
