A cluster of noninvoluting endocytic cells at the margin of the zebrafish blastoderm marks the site of embryonic shield formation
A cluster of noninvoluting endocytic cells at the margin of the zebrafish blastoderm marks the site of embryonic shield formation
复制标题
DOI：
10.1006/dbio.1996.0294
复制
发表时间：
1996-11-25
影响因子：
2.7
通讯作者：
DAmico, LA
中科院分区：
文献类型：
--
作者：
Cooper, MS;DAmico, LA
在斑马鱼胚胎中，新生的胚盾首先出现在中胚泡胚层的胚环中。这个位置定义了发育中的胚胎的背侧。在这篇文章中，我们报道胚轴形成的位置在胚泡晚期较早地被标记为具有独特的内吞活性的细胞团的出现。这一簇细胞由包膜层上皮细胞和一至两层深层细胞组成。与其他边缘的卵裂球不同，该簇中的细胞不参与胚层的退化，因为胚层经历了外胚层。这些未内化的内细胞性边缘(NEM)细胞可以通过在胚泡前期和胚泡中期应用膜不必要的荧光探针来选择性地标记。在胚盾形成过程中，NEM中的深层细胞。细胞团重新排列，并向前移位到胚层的前缘。当深层NEM细胞移动到这个位置时，它们就会成为一组被称为“前体细胞”的细胞。在60%-80%的胚胎期，前体细胞聚集成一个连贯的细胞团，在胚胚层的前缘形成一个楔形的帽子。在胚轴形成期间，深层细胞向胚胎中线迁移和汇聚，中线由前体细胞团的中心定义。在大约90%的胚胎期，前体细胞团被收缩的胚环重叠。在尾芽期，前体细胞形成库普弗氏囊泡的背侧顶，位于新生脊神经铰链的腹侧。在前人嫁接研究和已知背部基因表达模式的基础上，我们讨论了NEM/前体细胞簇在硬骨轴形成中可能发挥的作用。(C)1996年学术出版社。
In zebrafish embryos, the nascent embryonic shield first appears as a thickening in the germ ring of the mid-epiboly blastoderm. This site defines the dorsal side of the developing embryo. In this paper, we report that the site of embryonic axis formation is marked earlier at the late-blastula stage by the appearance of a cluster of cells with unique endocytic activities. This cluster of cells is composed of enveloping layer epithelial cells and one to two layers of underlying deep cells. Unlike other marginal blastomeres, cells in this cluster do not participate in involution as the blastoderm undergoes epiboly. These noninvoluting endocytic marginal (NEM) cells can be selectively labeled by applying membrane impermeant fluorescent probes to pre-epiboly and mid-epiboly embryos. During embryonic shield formation, deep cells in the NEM. cell cluster rearrange and are displaced forward to the leading edge of the blastoderm. As deep NEM cells move into this location, they become a group of cells known as ''forerunner cells.'' Between 60%- and 80%-epiboly, the forerunner cells coalesce into a coherent cell cluster that forms a wedge-shaped cap at the leading edge of the blastoderm. During embryonic axis formation, deep cells migrate and converge toward the embryonic midline, which is defined by the center of the forerunner cell cluster. At approximately 90% epiboly, the forerunner cell cluster becomes overlapped by the constricting germ ring. At tailbud stage, forerunner cells form the dorsal roof of Kupffer's vesicle, which is located ventral to the nascent chordoneural hinge. On the basis of previous grafting studies and known dorsal gene expression patterns, we discuss possible roles that the NEM/forerunner cell cluster may play in teleost axis formation. (C) 1996 Academic Press, Inc.