Intercalary muscle cell renewal in planarian pharynx
Intercalary muscle cell renewal in planarian pharynx
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DOI：
10.1007/s004270050249
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发表时间：
1999-04-01
影响因子：
2.4
通讯作者：
Romero, R
中科院分区：
文献类型：
--
作者：
Cebrià, F;Bueno, D;Romero, R
涡虫细胞更新是通过称为新生细胞的全能未分化细胞的增殖和分化来实现的。涡虫咽部内缺乏有丝分裂提出了细胞更新和生长如何在该器官内发生的问题。提出了两种解释：一种认为新细胞仍然靠近咽部底部，然后通过旧细胞的远端移位而生长，另一种则认为新细胞插入整个咽部的旧细胞之间。然而，第二种选择并没有解释新细胞如何进入咽部或它们如何到达最终目的地。在这项对涡虫咽内肌球蛋白重链基因表达的研究中，沿着咽实质检测到一排分化的肌细胞。根据杂交模式，所有这些肌细胞似乎都处于分化的早期阶段。这些数据支持咽部肌肉细胞更新的闰模型。根据该模型，咽底部的新生细胞将进入咽部，在那里它们开始分化为肌细胞，移动到上皮下肌肉组织并插入到旧的肌肉细胞之间。还讨论了这种嵌入模型在其他咽细胞类型中的可能应用。
Planarian cell renewal is achieved as a result of proliferation and differentiation of totipotent undifferentiated cells called neoblasts. The absence of mitosis within the planarian pharynx raises the question as to how cell renewal and growth occur within this organ. Two explanations have been advanced: one proposes that new cells remain close to the base of the pharynx, which then grows by distal displacement of older cells, and the other suggests that the new cells are intercalated between older cells throughout the pharynx. The second alternative, however, does not explain how new cells enter the pharynx or how they reach their final destination. In this study of myosin heavy-chain gene expression within planarian pharynx, a row of differentiating myocytes was detected all along the pharynx parenchyma. According to the hybridization pattern, all these myocytes appeared to be at early stages of differentiation. These data favour an intercalary model for muscle cell renewal within the pharynx. According to this model, neoblasts at the base of the pharynx would enter the pharynx, where they would start differentiation to myocytes, move to the subepithelial musculature and intercalate between the old muscle cells. The possible application of this intercalary model to other pharynx cell types is also discussed.