Amikura R M, Ihnuma M, Aikawa E, Yamada H, Nagano H
Department of Anatomy, Tokyo Women's Medical College, Japan.
Mol Reprod Dev. 1991 Jul;29(3):245-52. doi: 10.1002/mrd.1080290306.
When sea urchin embryos were subjected to nucleolar organizer region (NOR)-silver staining, densely stained particles were observed in the cytoplasm. The appearance of these cytoplasmic particles (CPs) was cell-cycle dependent. During early development, the CPs were detected at interphase, but not during mitosis; they disappeared at metaphase and reappeared at telophase. The CPs appeared periodically even when embryos were treated with cytochalasin B or aphidicolin, which inhibits the progression of cytokinesis and nuclear division, respectively. By contrast, CPs were not detected in the colchicine-treated embryos in which both cytokinesis and nuclear divisions were prevented. The CPs were observed only in the embryos whose stage was early blastula (about 6th to 7th cleavage) or earlier; no CPs were detected even at interphase in the embryos at late blastula (about 8th to 9th cleavage) or later. Electron microscopic evaluation showed CPs to be granular structures, similar to heavy bodies. Also, sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) showed that 95-kDa and 38-kDa proteins were the NOR-silver-staining proteins in sea urchin embryos. These proteins existed during the course of the cell cycles. These results suggest that (1) the cyclic appearance of the CPs or heavy bodies is closely related to the cell cycle as well as the programming of the embryogenesis, but independent of the cycle of cytokinesis and nuclear division; (2) 95-kDa and 38-kDa proteins are the major NOR-silver-staining proteins in sea urchin embryos.
当海胆胚胎进行核仁组织区（NOR）银染时，在细胞质中观察到密集染色的颗粒。这些细胞质颗粒（CPs）的出现依赖于细胞周期。在早期发育过程中，CPs在间期被检测到，但在有丝分裂期间未被检测到；它们在中期消失并在末期重新出现。即使胚胎用细胞松弛素B或阿非迪霉素处理，CPs也会周期性出现，这两种药物分别抑制胞质分裂和核分裂的进程。相比之下，在秋水仙碱处理的胚胎中未检测到CPs，在这种胚胎中胞质分裂和核分裂均被阻止。CPs仅在早期囊胚（约第6至7次卵裂）或更早阶段的胚胎中观察到；在晚期囊胚（约第8至9次卵裂）或更晚阶段的胚胎中，即使在间期也未检测到CPs。电子显微镜评估显示CPs是颗粒状结构，类似于重体。此外，十二烷基硫酸钠（SDS）-聚丙烯酰胺凝胶电泳（PAGE）表明，95 kDa和38 kDa的蛋白质是海胆胚胎中NOR银染蛋白质。这些蛋白质在细胞周期过程中存在。这些结果表明：（1）CPs或重体的周期性出现与细胞周期以及胚胎发生的编程密切相关，但独立于胞质分裂和核分裂周期；（2）95 kDa和38 kDa的蛋白质是海胆胚胎中主要的NOR银染蛋白质。
