Tension-dependent collective cell movements in the early gastrula ectoderm of Xenopus laevis embryos
Tension-dependent collective cell movements in the early gastrula ectoderm of Xenopus laevis embryos
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DOI：
10.1007/s004270050015
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发表时间：
2000-02-01
影响因子：
2.4
通讯作者：
Stein, AA
中科院分区：
文献类型：
--
作者：
Beloussov, LV;Louchinskaia, NN;Stein, AA
从非洲爪蟾早期原肠胚胚胎获取的腹侧外胚层外植体，通过施加于外植体内部层的两个相反的集中力或一个分布力进行人工拉伸。这些拉伸模式反映了正常发育过程中出现的不同力学情况。检测到对外加张力的两种主要运动学响应类型。首先，在集中拉伸开始后的15分钟内，外植体的相当一部分细胞呈现出朝着所施加拉伸力最近点的协同运动。我们将这种运动定义为趋张力性。之后，在集中拉伸和分布拉伸两种情况下，大多数细胞的轨迹重新定向为垂直于拉伸力，并且细胞开始在彼此之间水平和垂直地穿插。这伴随着外胚层外层细胞的广泛伸长以及细胞 - 细胞接触的重建。穿插运动首先导致拉伸诱导的张力大幅降低，然后形成特殊的双极“类胚体”形状。形态力学响应的类型和强度不取决于拉伸力相对于胚胎轴的方向。我们讨论了张力依赖性细胞运动中被动和主动成分的相互作用及其与正常形态发生事件的关系。
Ventral ectodermal explants taken from early gastrula embryos of Xenopus laevis were artificially stretched either by two opposite concentrated forces or by a distributed force applied to the internal explant's layer. These modes of stretching reflect different mechanical situations laking place in the normal development. Two main types of kinematic response to the applied tensions were detected. First, by 15 min after the onset of concentrated stretching a substantial proportion of the explant's cells exhibited a concerted movement towards the closest point of the applied stretching force. We define this movement as tensotaxis. Later, under both concentrated and distributed stretching, most of the cell's trajectories became reoriented perpendicular to the stretching force, and the cells started to intercalate between each other, both horizontally and vertically. This was accompanied by extensive elongation of the outer ectodermal cells and reconstruction of cell-cell contacts. The intercalation movements led first to a considerable reduction in the stretch-induced tensions and then to the formation of peculiar bipolar "embryoid" shapes. The type and intensity of the morphomechanical responses did nut depend upon the orientation of a stretching force in relation to the embryonic axes. We discuss the interactions of the passive and active components in tension-dependent cell movements and their relations to normal morphogenetic events.