Stage- and tissue-specific patterns of cell division in embryonic and larval tissues of amphioxus during normal development
Stage- and tissue-specific patterns of cell division in embryonic and larval tissues of amphioxus during normal development
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DOI：
10.1111/j.1525-142x.2006.00085.x
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发表时间：
2006-03-01
影响因子：
2.9
通讯作者：
Holland, LZ
中科院分区：
文献类型：
--
作者：
Holland, ND;Holland, LZ
描述了用溴脱氧尿苷标记的文昌鱼（Branchiostoma floridae）的胚胎和幼虫的分裂细胞的分布。由于细胞分裂是针对所有发育组织进行评估的，因此这是对缺乏定型细胞谱系的动物的发育细胞增殖的首次全面研究。在文昌鱼中，细胞分裂在卵裂期间实际上是同步的，但在囊胚阶段变得异步。从神经胚阶段开始，在中胚层起源之后，体节中胚层和脊索中分裂细胞的比例逐渐下降。然而，其他组织却偏离了这种模式。例如，在中神经叶中，神经板前端有短暂而强烈的有丝分裂爆发。此外，从神经胚到早期幼虫阶段，所有外胚层细胞都停止分裂并发育出纤毛，推动动物在水中前进；随后，在后期幼虫的表皮中，有丝分裂恢复，纤毛细胞的比例下降，肌肉起伏逐渐取代纤毛进行游动。最后，在早期幼虫中，三种细胞类型的细胞分裂出现终末期停滞，这些细胞类型一旦张开嘴就早期分化参与摄食，即产生摄食电流的纤毛咽细胞以及将捕获食物的粘液输出到咽部的棒状腺和内柱的分泌细胞。总之，细胞增殖强度的这些阶段和组织特异性变化说明了胚胎和幼虫自然史的要求如何影响发育程序。
The distribution of dividing cells is described for embryos and larvae of amphioxus (Branchiostoma floridae) pulse labeled with bromodeoxyuridine. Because cell division is assessed for all of the developing tissues, this is the first comprehensive study of developmental cell proliferation for an animal lacking a stereotyped cell lineage. In amphioxus, cell divisions are virtually synchronous during cleavage, but become asynchronous at the blastula stage. Starting at the neurula stage, after the origin of the mesoderm, the proportion of dividing cells progressively declines in the somitic mesoderm and notochord. Other tissues, however, deviate from this pattern. For example, in the mid-neurula, there is a brief, intense burst of mitosis at the anterior end of the neural plate. Also, from the neurula through the early larval stage, all of the ectoderm cells cease dividing and develop cilia that propel the animal through the water; subsequently, in the epidermis of later larvae, mitosis resumes and the proportion of ciliated cells declines as muscular undulation gradually replaces ciliation for swimming. Finally, in the early larvae, there is a terminal arrest of cell division in three cell types that differentiate early to participate in feeding as soon as the mouth opens-namely the ciliated pharyngeal cells that produce the feeding current and the secretory cells of the club-shaped gland and endostyle that export food-trapping mucus into the pharynx. In sum, these stage- and tissue-specific changes in cell proliferation intensity illustrate how the requirements of embryonic and larval natural history can shape developmental programs.