Sahali D, Mulliez N, Chatelet F, Laurent-Winter C, Citadelle D, Sabourin J C, Roux C, Ronco P, Verroust P
INSERM U64, Hôpital Tenon, Paris, France.
Am J Pathol. 1993 May;142(5):1654-67.
We have previously shown that monoclonal antibodies specific for a 280-kd protein (gp280) concentrated within the coated pits of renal and yolk sac brush border-induced fetal malformations, whereas antibodies specific for gp330, another coated pit protein with a similar distribution, had no deleterious effect on embryonic development. In this study, we show that gp280 and gp330 are closely related proteins, as indicated by: 1) similarities in peptide maps obtained after cyanogen bromide cleavage, 2) immunological cross-reactivity related to a minor contingent of antibodies that do not have teratogenic activity, and 3) asynchronous but related expressions during ontogenesis. During the early stages of development, the expression of the two glycoproteins was limited to (gp330) or predominant in (gp280) the clathrin-coated pits and intermicrovillar areas. In the pre-implantation embryo, gp330 was expressed by trophectodermal cells, which became negative in day-6 embryos trapped in endometrial infoldings. At this stage, gp280 and gp330 were both simultaneously detectable at the apical pole of the first entoblastic cells and remained expressed by the brush border of visceral yolk sac epithelial cells until the end of pregnancy. In addition, gp330 was expressed by amniotic cells and neurectodermal structures. During nephrogenesis, in contrast, the expression of gp280 and gp330 by the intermicrovillar areas of the proximal tubule cell was the result of a complex maturation process. gp280 and gp330 were diffusely distributed in S-shaped bodies in the presumptive areas of the glomerulus, proximal tubule, and distal tubule (gp330). During development of the nephron, the pattern of expression became progressively restricted to the proximal tubule and glomerulus (gp330), and selective localization in the intermicrovillar areas was only achieved in filtrating nephrons.
我们之前已经表明，针对一种280-kd蛋白（gp280）的单克隆抗体集中在肾和卵黄囊刷状缘的包被小窝内，可导致胎儿畸形，而针对gp330（另一种分布相似的包被小窝蛋白）的抗体对胚胎发育没有有害影响。在本研究中，我们表明gp280和gp330是密切相关的蛋白，这表现为：1）溴化氰裂解后获得的肽图相似；2）与一小部分不具有致畸活性的抗体相关的免疫交叉反应性；3）个体发育过程中不同步但相关的表达。在发育早期，这两种糖蛋白的表达局限于（gp330）或主要存在于（gp280）网格蛋白包被小窝和微绒毛间区域。在植入前胚胎中，gp330由滋养外胚层细胞表达，在被困于子宫内膜褶皱中的第6天胚胎中变为阴性。在此阶段，gp280和gp330在第一批内胚层细胞的顶端同时可检测到，并在内脏卵黄囊上皮细胞的刷状缘持续表达直至妊娠末期。此外，gp330由羊膜细胞和神经外胚层结构表达。相反，在肾发生过程中，近端小管细胞微绒毛间区域gp280和gp330的表达是一个复杂成熟过程的结果。gp280和gp330在肾小球、近端小管和远端小管（gp330）的假定区域的S形体中呈弥漫性分布。在肾单位发育过程中，表达模式逐渐局限于近端小管和肾小球（gp330），并且只有在滤过性肾单位中才在微绒毛间区域实现选择性定位。
