Lovell-Badge R H, Evans M J, Bellairs R
J Embryol Exp Morphol. 1985 Feb;85:65-80.
Tissues dissected from early chick embryos were labelled in vitro with [35S]methionine, and their patterns of polypeptide synthesis investigated using the technique of two-dimensional (2-D) polyacrylamide gel electrophoresis. Apart from providing a preliminary description of the molecular changes associated with the processes of gastrulation and segmentation in the chick embryo, this study has revealed a number of polypeptides that may be useful as markers of cell type or function. The protein synthetic patterns of hypoblast from early and late gastrulae (stages 2 and 4, respectively: Hamburger & Hamilton, 1951) and of definitive endoblast and junctional endoblast from late gastrulae all resemble one another closely, but differ markedly from that of the epiblast at either stage. The lower layer tissues are characterized by the presence of eleven polypeptides that are largely absent from the epiblast. These findings are discussed with reference to current theories on the origins of the lower layer tissues. Comparisons between the 2-D patterns for tissues dissected from gastrulae and from embryos undergoing segmentation (stage 12) have revealed ten polypeptides showing stage-specific rather than tissue-specific expression. Apart from these ten polypeptides, the 2-D patterns for epiblast and ectoderm were practically identical, and distinguishable from those of other tissues by a lack of any unique polypeptides. On the other hand, stage-4 endoblast and stage-12 endoderm differed in the expression of many polypeptides. One polypeptide was found that may be considered as a marker of mesodermal cell type, as it was present in lateral plate, segmental plate and somitic mesoderm, but not in tissues of the other germ layers. Lateral plate could be distinguished from the other mesodermal tissues in the expression of a number of polypeptides, but the similarity in the 2-D patterns for segmental plate and somites suggest that the separation of somites from the anterior end of the segmental plate is not accompanied by the synthesis of new polypeptides.
从早期鸡胚中分离出的组织在体外用[35S]甲硫氨酸进行标记，并用二维（2-D）聚丙烯酰胺凝胶电泳技术研究其多肽合成模式。除了对与鸡胚原肠胚形成和体节形成过程相关的分子变化进行初步描述外，本研究还揭示了一些多肽，它们可能用作细胞类型或功能的标志物。早期和晚期原肠胚（分别为第2和第4阶段：Hamburger & Hamilton，1951）的下胚层以及晚期原肠胚的确定内胚层和连接内胚层的蛋白质合成模式彼此非常相似，但与任一阶段的上胚层明显不同。下层组织的特征是存在11种在上胚层中基本不存在的多肽。结合当前关于下层组织起源的理论对这些发现进行了讨论。对从原肠胚和进行体节形成的胚胎（第12阶段）中分离出的组织的二维模式进行比较，发现有10种多肽呈现阶段特异性而非组织特异性表达。除了这10种多肽外，上胚层和外胚层的二维模式几乎相同，并且由于缺乏任何独特的多肽而与其他组织的模式区分开来。另一方面，第4阶段的内胚层和第12阶段的内胚层在许多多肽的表达上有所不同。发现一种多肽可被视为中胚层细胞类型的标志物，因为它存在于侧板、体节板和体节中胚层，但不存在于其他胚层的组织中。侧板在许多多肽的表达上可与其他中胚层组织区分开来，但体节板和体节的二维模式相似，这表明体节从体节板前端分离时并未伴随着新多肽的合成。
