Dowsing A T, Gougoulidis T, Dowsing B J, Draber P, Trounson A O
Centre for Early Human Development, Monash University, Monash Medical Centre, Clayton, Victoria, Australia.
Mol Reprod Dev. 1998 Jan;49(1):19-28. doi: 10.1002/(SICI)1098-2795(199801)49:1<19::AID-MRD3>3.0.CO;2-R.
The preimplantation developmental period is associated with constant changes within the embryo, and some of these changes are apparent on the embryo cell surface. For example, during transition from maternal to embryonic genome control and the compaction and differentiation of embryonic cells, the cell surface undergoes morphologic alterations that reflect changes in gene control. In order to gain insight into the events occurring during embryonic development and cellular differentiation, monoclonal antibodies specific for cell surface antigens (TEC antigens) of embryonic cells have been generated previously and shown to recognise either the carbohydrate moiety of embryoglycan or a developmentally regulated protein epitope. The TEC antigens have been identified on mouse preimplantation embryos, and their expression is specific to particular developmental stages. To determine whether these antigens are conserved in higher mammals, we examined the expression of four TEC antigens (TEC-1 to TEC-4) on in vitro-derived bovine and murine embryos during the preimplantation stage of development. It was found that bovine oocytes and embryos derived from in vitro maturation (IVM) and in vitro fertilisation (IVF) showed stage-specific expression of each of the TEC antigens investigated, with the pattern of expression overlapping but not identical to that seen in the mouse. Immunoprecipitation together with Western blot analysis showed that the TEC monoclonal antibodies recognised a single glycoprotein band with an apparent molecular weight of 70 kDa. Confocal microscopy of immunofluorescence staining of the bovine cells showed this protein to be located on the cell surface. The apparent negative expression of these TEC antigens by immunohistochemistry and immunoprecipitation at particular stages of development appears to be due to the epitopes being inaccessible to the TEC antibodies, since Western blotting revealed the TEC antigens to be present at all stages of development examined. Antibodies identifying stage-specific antigens will provide useful markers to characterise early embryonic cells, monitor normal embryonic development in vitro, and identify cell surface structures having a function in cell-cell interactions during embryogenesis and differentiation.
植入前发育阶段与胚胎内的持续变化相关，其中一些变化在胚胎细胞表面很明显。例如，在从母体基因组控制向胚胎基因组控制的转变以及胚胎细胞的致密化和分化过程中，细胞表面会发生形态学改变，这些改变反映了基因控制的变化。为了深入了解胚胎发育和细胞分化过程中发生的事件，先前已产生了针对胚胎细胞表面抗原（TEC抗原）的单克隆抗体，并显示其可识别胚胎聚糖的碳水化合物部分或发育调控的蛋白质表位。TEC抗原已在小鼠植入前胚胎上得到鉴定，其表达特定于特定发育阶段。为了确定这些抗原在高等哺乳动物中是否保守，我们研究了体外培养的牛和小鼠胚胎在植入前发育阶段四种TEC抗原（TEC-1至TEC-4）的表达。结果发现，体外成熟（IVM）和体外受精（IVF）获得的牛卵母细胞和胚胎显示出所研究的每种TEC抗原的阶段特异性表达，其表达模式与小鼠中的重叠但不完全相同。免疫沉淀结合蛋白质印迹分析表明，TEC单克隆抗体识别出一条表观分子量为70 kDa的单一糖蛋白条带。对牛细胞进行免疫荧光染色的共聚焦显微镜检查显示该蛋白位于细胞表面。在特定发育阶段通过免疫组织化学和免疫沉淀法检测到这些TEC抗原明显呈阴性表达，这似乎是由于表位无法被TEC抗体识别，因为蛋白质印迹显示在所检查的所有发育阶段都存在TEC抗原。识别阶段特异性抗原的抗体将为表征早期胚胎细胞、监测体外正常胚胎发育以及鉴定在胚胎发生和分化过程中具有细胞间相互作用功能的细胞表面结构提供有用的标记。
