Kallenbach R J
J Cell Sci. 1985 Feb;73:261-78. doi: 10.1242/jcs.73.1.261.
Two approaches were used to study the origin and overall development of cytasters in relation to the emergence and maturation of new centrioles in sea-urchin eggs. A continuous hypertonic treatment was used to gather information on cytoplasmic areas of potential cytaster formation and the subsequent development of these cytastral areas. A two-step parthenogenetic stimulation procedure was used to analyse various cytastral changes during and after mitosis. Potential cytastral areas are associated with extensive Golgi complexes and astral formation occurs only about newly induced centrioles. The construction of a single aster involves a large redistribution of local cytoplasmic structures, concentrating some components, excluding others and orienting more and more microtubules in an increasingly focussed arrangement. These events are correlated with an extensive accumulation of astral endoplasmic reticulum, an increase in the size of the astral area, and a gradual acquisition of a more typical radial configuration. The astral shape becomes more pronounced during mitosis, after which the cytasters regress, but retain the mature centrioles. The data reveal that cytaster formation is initiated after the activation and appearance of centriolar precursor bodies, and that both centrioles and associated cytasters are complementary structures, which develop in unison. The results suggest that developing centrioles, from the moment of their emergence, control and direct the events of cytastral formation.
采用了两种方法来研究星状体的起源和整体发育，以及它们与海胆卵中新中心粒的出现和成熟之间的关系。采用连续高渗处理来收集有关潜在星状体形成的细胞质区域以及这些星状体区域后续发育的信息。采用两步孤雌生殖刺激程序来分析有丝分裂期间和之后的各种星状体变化。潜在的星状体区域与广泛的高尔基体复合体相关，星状体形成仅发生在新诱导的中心粒周围。单个星体的构建涉及局部细胞质结构的大量重新分布，集中一些成分，排除其他成分，并使越来越多的微管以越来越集中的排列方式定向。这些事件与星状内质网的大量积累、星体区域大小的增加以及逐渐获得更典型的放射状构型相关。星体形状在有丝分裂期间变得更加明显，之后星状体退化，但保留成熟的中心粒。数据表明，星状体形成在中心粒前体激活并出现后开始，并且中心粒和相关的星状体都是互补结构，它们协同发育。结果表明，发育中的中心粒从出现之时起就控制并指导星状体形成事件。
