Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy.
Department of Medical Biotechnologies, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy.
Cells. 2020 Jan 3;9(1):115. doi: 10.3390/cells9010115.
Drosophila spermatocytes have giant centrioles that display unique properties. Both the parent centrioles maintain a distinct cartwheel and nucleate a cilium-like region that persists during the meiotic divisions and organizes a structured sperm axoneme. Moreover, the parent centrioles are morphologically undistinguishable, unlike vertebrate cells in which mother and daughter centrioles have distinct structural features. However, our immunofluorescence analysis of the parent centrioles in mature primary spermatocytes revealed an asymmetric accumulation of the typical Sas4 and Sas6 proteins. Notably, the fluorescence intensity of Sas4 and Sas6 at the daughter centrioles is greater than the intensity found at the mother ones. In contrast, the centrioles of wing imaginal disc cells display an opposite condition in which the loading of Sas4 and Sas6 at the mother centrioles is greater. These data underlie a subtle asymmetry among the parent centrioles and point to a cell type diversity of the localization of the Sas4 and Sas6 proteins.
果蝇精母细胞具有独特性质的巨大中心粒。亲代中心粒均保持独特的辐轮结构，并起始形成类似于纤毛的区域，该区域在减数分裂过程中持续存在，并组织形成有结构的精子鞭毛轴丝。此外，亲代中心粒在形态上无法区分，与脊椎动物细胞不同，脊椎动物细胞中母源和子源中心粒具有独特的结构特征。然而，我们对成熟初级精母细胞中亲代中心粒的免疫荧光分析显示，典型的 Sas4 和 Sas6 蛋白呈现不对称积累。值得注意的是，子源中心粒上 Sas4 和 Sas6 的荧光强度大于母源中心粒上的强度。相比之下，翅 imaginal 盘细胞的中心粒呈现相反的情况，即 Sas4 和 Sas6 在母源中心粒上的加载量更大。这些数据表明亲代中心粒之间存在细微的不对称性，并指出 Sas4 和 Sas6 蛋白定位存在细胞类型多样性。
