Ohtaka Ayami, Okuzaki Daisuke, Saito Takamune T, Nojima Hiroshi
Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka 565-0871, Japan.
Eukaryot Cell. 2007 Jun;6(6):971-83. doi: 10.1128/EC.00016-07. Epub 2007 Apr 13.
Some meiosis-specific proteins of Schizosaccharomyces pombe harbor coiled-coil motifs and play essential roles in meiotic progression. Here we describe Mcp4, a novel meiosis-specific protein whose expression is abruptly induced at the horsetail phase and which remains expressed until sporulation is finished. Fluorescence microscopic analysis revealed that Mcp4 alters its subcellular localization during meiosis in a manner that partially resembles the movement of F-actin during meiosis. Mcp4 and F-actin never colocalize; rather, they are located in a side-by-side manner. When forespore membrane formation begins at metaphase II, the Mcp4 signals assemble at the lagging face of the dividing nuclei. At this stage, they are sandwiched between F-actin and the nucleus. Mcp4, in turn, appears to sandwich F-actin with Meu14. In mcp4Delta cells at anaphase II, the F-actin, which is normally dumbbell-shaped, adopts an abnormal balloon shape. Spores of mcp4Delta cells were sensitive to NaCl, although their shape and viability were normal. Taken together, we conclude that Mcp4 plays a role in the accurate positioning of F-actin during S. pombe meiosis.
粟酒裂殖酵母的一些减数分裂特异性蛋白含有卷曲螺旋基序，并在减数分裂进程中发挥重要作用。在此，我们描述了Mcp4，一种新的减数分裂特异性蛋白，其表达在马尾藻期突然被诱导，并且在孢子形成完成之前一直保持表达。荧光显微镜分析显示，Mcp4在减数分裂过程中改变其亚细胞定位，其方式部分类似于减数分裂期间F-肌动蛋白的运动。Mcp4和F-肌动蛋白从不共定位；相反，它们以并排的方式定位。当在中期II开始前孢子膜形成时，Mcp4信号在分裂细胞核的滞后面聚集。在这个阶段，它们夹在F-肌动蛋白和细胞核之间。反过来，Mcp4似乎将F-肌动蛋白与Meu14夹在一起。在减数分裂后期II的mcp4Delta细胞中，通常呈哑铃形的F-肌动蛋白呈现出异常的气球形状。mcp4Delta细胞的孢子对NaCl敏感，尽管它们的形状和活力正常。综上所述，我们得出结论，Mcp4在粟酒裂殖酵母减数分裂过程中F-肌动蛋白的准确定位中发挥作用。
