MICROTUBULES AND MICROFILAMENTS IN NEWT NEURULATION
MICROTUBULES AND MICROFILAMENTS IN NEWT NEURULATION
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DOI：
10.1016/0012-1606(71)90073-x
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发表时间：
1971-01-01
影响因子：
2.7
通讯作者：
BURNSIDE, B
中科院分区：
文献类型：
--
作者：
BURNSIDE, B
在有尾目神经形成期间，假定的神经细胞伸长以形成神经板，然后随着板卷起而顶部收缩以形成神经管。在同一时期，表皮细胞逐渐变平。这些细胞的电子显微镜已经进行了尝试，以了解形态发生细胞形状变化的机制。在伸长的神经板细胞中，微管平行于长轴定向。这些“旁轴”微管的数量计数每个细胞在三个apicobasal水平的细胞没有显着不同，因此，它是实际的，考虑作为一个单一的人口的全细胞长度的微管旁轴微管。每个细胞的近轴微管的数量随着细胞的伸长而显著减少，但是在给定的阶段，细胞的伸长程度与其所包含的近轴微管的数量并不密切相关。一些观察结果表明，微管有助于细胞伸长的某种形式的运输机制。在神经外胚层细胞的顶端收缩过程中，环绕细胞顶端的微丝环束的厚度显著增加。在束厚度的增加和减少的细胞顶端的周长之间的反比关系表明，这些过程的结果从增加重叠和交错的原始补充顶端丝。扁平的表皮细胞显示出随机取向的微管和成束的较粗的细丝（直径70-100 μ m），这些细丝使人联想到“张力原纤维”，并且似乎从桥粒跨越细胞到桥粒。
During urodele neurulation, presumptive neural cells elongate to form the neural plate and then constrict apically as the plate rolls up to form the neural tube. During the same period, epidermal cells gradually flatten. Electron microscopy of these cells has been carried out in an attempt to understand the mechanism of morphogenetic cell shape changes. In elongating neural plate cells, microtubules are oriented parallel to the long axis. Counts of numbers of these “paraxial” microtubules per cell do not differ significantly at three apicobasal levels of the cells; therefore, it is practical to consider the paraxial microtubules as a single population of full-cell-length microtubules. The number of paraxial microtubules per cell decreases significantly as the cell elongates, but the degree of elongation of a cell at a given stage is not closely related to the number of paraxial microtubules it contains. Several observations suggest that microtubules contribute to cell elongation by some form of transport mechanism. During the apical constriction of neural ectoderm cells, there is marked increase in thickness of a circumferential bundle of microfilaments which encircles the cell apex. The inverse relationship between increase in bundle thickness and decrease in circumference of the cell apex suggests that these processes result from increased overlap and interdigitation of the original complement of apical filaments. Flattening epidermal cells display randomly oriented microtubules and bundles of thicker filaments (70–100 Å in diameter) which are reminiscent of “tonofibrils” and appear to span the cell from desmosome to desmosome.