Callaini G, Whitfield W G, Riparbelli M G
Department of Evolutionary Biology, University of Siena, Italy.
Exp Cell Res. 1997 Jul 10;234(1):183-90. doi: 10.1006/excr.1997.3618.
We have used immunofluorescence and electron microscopy to examine centrosome dynamics during the first postblastodermic mitoses in the Drosophila embryo. The centrosomal material, as recognized by antibodies against CP190 and gamma-tubulin, does not show the typical shape changes observed in syncytial embryos, but remains compact throughout mitosis. Centrioles, however, behave as during the syncytial mitoses, with each daughter cell inheriting two separated centrioles at the end of telophase. During interphase in epithelial cells that have a distinct G1 phase, two isolated centrioles are found, suggesting that the separation of sister centrioles is tightly coupled to a mitotic oscillator in both the "abbreviated" and the "complete" embryonic division cycles. The centrioles of the Drosophila embryo sharply differed from the sperm basal body, having a cartwheel structure with nine microtubular doublets and a central tubule. This "immature" centriolar morphology was shown to persist throughout embryonic development, clearly demonstrating that these centrioles are able to replicate despite their apparently neotenic structure.
我们利用免疫荧光和电子显微镜技术，研究了果蝇胚胎胚盘后首次有丝分裂过程中的中心体动力学。通过针对CP190和γ-微管蛋白的抗体识别出的中心体物质，并未表现出在合胞体胚胎中观察到的典型形状变化，而是在整个有丝分裂过程中保持紧密状态。然而，中心粒的行为与合胞体有丝分裂期间相同，在末期结束时，每个子细胞继承两个分离的中心粒。在具有明显G1期的上皮细胞间期，发现了两个孤立的中心粒，这表明在“缩短”和“完整”的胚胎分裂周期中，姐妹中心粒的分离都与有丝分裂振荡器紧密耦合。果蝇胚胎的中心粒与精子基体明显不同，具有带有九个微管双联体和一个中央微管的轮辐结构。这种“不成熟”的中心粒形态在整个胚胎发育过程中持续存在，清楚地表明这些中心粒尽管其结构明显呈幼态持续，但仍能够进行复制。
