Huang L F, Levinhar L, Ginsburg M, Lee K G, Cohen W D
Department of Biological Sciences, Hunter College, New York, New York 10021, USA.
Cell Biol Int. 2001;25(12):1229-36. doi: 10.1006/cbir.2001.0800.
Non-mammalian vertebrate erythrocytes are flattened nucleated ellipsoids containing marginal bands (MBs) of microtubules that assemble during cellular morphogenesis. Earlier work suggested that pointed erythroid cells containing pointed MBs were intermediate stages in terminal differentiation, rather than aberrant forms, but direct evidence was lacking. Here we report on morphogenesis in individual post-cytokinetic amphibian erythroblasts in culture. Daughter cells remained adjacent in pairs, and developed pointed morphology over 1-2 h in the following sequence: (a) ends opposite the cytokinetic furrow became pointed, producing a spheroidal singly-pointed stage; (b) furrow ends usually became pointed, yielding doubly-pointed cells; (c) furrow-end points disappeared, producing a second singly-pointed stage that was flattening. Over a longer term, the single points sometimes disappeared, yielding a flattened discoid. These observations support the hypothesis that pointed cells are normal intermediates in a biogenetic program in which post-mitotic centrosomes organize MBs while occupying the singly-pointed ends of differentiating erythroblasts.
非哺乳动物脊椎动物的红细胞是扁平的有核椭球体，其中含有在细胞形态发生过程中组装的微管边缘带（MBs）。早期的研究表明，含有尖锐MBs的尖头红细胞是终末分化的中间阶段，而非异常形态，但缺乏直接证据。在此，我们报告了培养的单个细胞分裂后两栖类成红细胞的形态发生。子细胞成对相邻，并在1-2小时内按以下顺序发育出尖头形态：（a）与细胞分裂沟相对的末端变尖，形成球形单尖头阶段；（b）沟端通常变尖，产生双尖头细胞；（c）沟端的尖消失，产生第二个正在变平的单尖头阶段。从更长期来看，单个的尖有时会消失，产生扁平的盘状细胞。这些观察结果支持了这样的假设，即尖头细胞是生物发生程序中的正常中间阶段，在该程序中，有丝分裂后的中心体在占据分化成红细胞单尖头末端的同时组织MBs。
