An analysis of in vivo cell migration during teleost fin morphogenesis.
An analysis of in vivo cell migration during teleost fin morphogenesis.
复制标题
硬骨鱼鳍形态发生过程中体内细胞迁移的分析。
作者：
A. Wood;P. Thorogood
在硬骨鱼胚胎胸鳍芽最初显示顶端外胚层脊沿着其整个远端边缘。随着远端外胚层上皮生长并折叠以封闭上皮的并置基底表面之间的细胞外空间，嵴随后转变为顶端折叠。直径达2微米的胶原原纤维，称为“放线菌”，沿近端-远端轴沿着沉积成两个（背侧和腹侧）阵列。放线菌彼此平行排列，沿其长度的大部分沿着具有规则的间距。间充质细胞从鳍芽的基部向远端迁移，遇到背侧和腹侧的放线菌阵列，并在它们之间移动，显然使用原纤维作为底层。整个结构是透明的，并使用的鳉鱼，我们已经调查了间充质细胞的迁移之间的135和220小时的发展，使用Nomarski干涉相差显微镜和延时录像。在观察期间，每个细胞的细胞突起数量显著增加。这些过程可以根据它们的直径分级。直径大于2微米的突起通常不会沿着放线菌排列，而是出现在细胞体的任何方面。与此相反，直径小于2微米的过程似乎被限制在迁移细胞的远端方面，并显示出越来越多的趋势，成为对齐的发展进展。延时视频记录显示，这种对准的过程比非对准的过程（平均速度4.66（+/-0.67）微米/小时）移动得更快（平均速度17.98（+/-2.25）微米/小时）。全细胞移位通常比突起移动的速率慢：（1.52（+/- 0.36）微米/小时）之间的发展记录135和160小时上升到最大平均速率（4.72（+/- 0.42）微米/小时）;细胞移位速率最快的时期与沿沿着放线菌的最大突起排列相关。薄的1微米塑料切片显示，一般来说，对齐的过程是在密切相关的表面的放线菌原纤维，而不是它们之间的空间。
In the teleost embryo the pectoral fin bud initially displays an apical ectodermal ridge along its entire distal margin. The ridge subsequently becomes transformed into an apical fold as the distal ectodermal epithelium grows and folds to enclose an extracellular space between the apposed basal surfaces of the epithelium. Collagen fibrils up to 2 micron in diameter, termed 'actinotrichia', are deposited along the proximo-distal axis in two (dorsal and ventral) arrays. The actinotrichia are aligned parallel to one another with a regular spacing along the greater part of their length. Mesenchymal cells migrating distally from the base of the fin bud encounter the dorsal and ventral arrays of actinotrichia and move between them apparently using the fibrils as a substratum. The entire structure is transparent and, using the killifish Aphyosemion scheeli, we have investigated the migration of the mesenchymal cells between 135 and 220 h of development, using Nomarski interference contrast microscopy and time-lapse video recording. The number of cellular processes per cell increased significantly during the period of observation. These processes could be graded according to their diameters. Processes of diameter greater than 2 micron were not usually aligned along actinotrichia and arose at any aspect of the cell body. In contrast, processes with diameters less than 2 micron appeared to be confined to the distal aspects of the migrating cells and showed an increasing tendency to become aligned as development progressed. Time-lapse video recordings revealed that such aligned processes move faster (mean speed 17.98 (+/- 2.25) micron/h) than non-aligned processes (mean speed 4.66 (+/- 0.67) micron/h). Whole cell translocation was generally slower than rates of process movement: the lowest mean value (1.52(+/- 0.36) micron/h) was recorded between 135 and 160 h of development rising to a maximum mean rate (4.72(+/- 0.42) micron/h) between 195 and 220 h; the period of the fastest rate of cell translocation correlated with maximum process alignment along actinotrichia. Thin 1 micron plastic sections revealed that, generally, aligned processes were in close association with the surface of the actinotrichial fibrils and not the spaces between them.