Menzel D
Max-Planck Institute for Cell Biology, Ladenburg, Germany.
Curr Opin Cell Biol. 1996 Feb;8(1):38-42. doi: 10.1016/s0955-0674(96)80046-9.
Selected algal species continue to serve as model organisms for the study of cell growth and cellular morphogenesis. Recent improvements in immunohistochemical and microinjection methods have helped to consolidate our views of the role of the cytoskeleton as a generator of spatial patterns in the cytoplasm before cellular morphogenesis. Progress has also been made in the discovery and characterization of molecular components of both the cytoskeleton and the extracellular matrix (ECM). Studies on the oocytes of fucoid brown algae have demonstrated that the ECM serves an active role in controlling cell shape and in defining the developmental fate of a cell. Actin, transmembrane proteins of the beta-integrin type, and vitronectin-like proteins in the ECM have been discussed as important elements in polar axis formation in the early steps of post-fertilization development. The mechanism of cell expansion has been investigated in the large coenocytic cells of the siphonoclad green algae. It was shown that the alignment of cell wall microfibrils in these cells depends on the degree of order in the cortical microtubule system. However, in contrast to earlier hypotheses, microtubules do not appear to function as physical boundaries guiding the paths of cellulose synthesizing terminal complexes in the plane of the plasma membrane. Recent work on the giant unicellular green alga Acetabularia has revealed dynamic reorganizations of the actin cytoskeleton during the course of apical morphogenesis. Actin has also been suggested to play a role, in more subtle ways, in the establishment of membrane prepatterns during cellular morphogenesis of the desmid green alga Micrasterias, prepatterns that predict regions of future surface expansion.
某些藻类物种持续作为研究细胞生长和细胞形态发生的模式生物。免疫组织化学和显微注射方法最近的改进，有助于巩固我们对于细胞骨架在细胞形态发生之前作为细胞质中空间模式生成器的作用的认识。在细胞骨架和细胞外基质（ECM）的分子成分的发现和表征方面也取得了进展。对岩藻褐藻卵母细胞的研究表明，细胞外基质在控制细胞形状和确定细胞的发育命运方面发挥着积极作用。肌动蛋白、β-整合素类型的跨膜蛋白以及细胞外基质中的玻连蛋白样蛋白，已被讨论为受精后发育早期极轴形成中的重要元素。已在管藻绿藻的大型多核细胞中研究了细胞扩张的机制。结果表明，这些细胞中细胞壁微纤丝的排列取决于皮质微管系统的有序程度。然而，与早期的假设相反，微管似乎并不作为在质膜平面中引导纤维素合成末端复合物路径的物理边界发挥作用。最近对大型单细胞绿藻伞藻的研究揭示了在顶端形态发生过程中肌动蛋白细胞骨架的动态重组。肌动蛋白也被认为在鼓藻绿藻微星鼓藻细胞形态发生过程中以更微妙的方式在膜预模式的建立中发挥作用，这些预模式预测未来表面扩张的区域。
