Ogilvie S, Kvello-Stenstrom A G, Hammond G, Buhi W C, Larkin L H, Shiverick K T
Department of Pharmacology and Therapeutics, University of Florida, Gainesville 32610.
Endocrinology. 1989 Jul;125(1):287-94. doi: 10.1210/endo-125-1-287.
Human pregnancy-specific beta 1-glycoprotein (hPS beta G) consists of a set of glycoproteins present in placenta and maternal serum. This study characterized proteins in rat placenta that show immunological cross-reactivity with antisera to hPS beta G. Immunocytochemical studies using two independent preparations of anti-hPS beta G showed intense specific staining within basophilic cytotrophoblast cells of the basal zone of the gestation day 15 rat placenta. In contrast, basophilic cytotrophoblasts located in the labyrinth did not stain. Subsequent experiments used gel electrophoresis and immunoblot analysis to compare PS beta G in human placenta and serum with immunoreactive proteins in rat placenta and serum. A set of two or three proteins was detected in human villous tissue and pregnancy serum with apparent mol wt (Mr) ranging from 54,000-76,000. In contrast rat placenta showed a major immunoreactive protein with 120,000 Mr, while rat serum contained bands of 48,000 64,000 and 69,000 Mr. Explant cultures of rat basal zone tissue secreted two [35S]methionine-labeled proteins that were immunoreactive, a major 120,000 Mr species and a minor 76,000 Mr form, with pI values of 4.6-5.5; tunicamycin inhibited the secretion of both species. Thus, a 120,000 Mr glycoprotein appears to be the major tissue and secreted form of rat PS beta G analog in day 15 placenta. Finally, the cytochemical localization of PS beta G-like proteins in rat placenta showed a progressive gestational shift from giant trophoblast cells in the parietal yolk sac placenta on day 12 to the basal zone cytotrophoblast cells by day 15. Data indicate that the pregnant rat may provide an animal model for investigation of the biological function of PS beta G during late gestation.
人妊娠特异性β1-糖蛋白（hPSβG）由一组存在于胎盘和母体血清中的糖蛋白组成。本研究对大鼠胎盘中与抗hPSβG抗血清呈现免疫交叉反应的蛋白质进行了表征。使用两种独立制备的抗hPSβG进行的免疫细胞化学研究显示，在妊娠第15天大鼠胎盘基底层的嗜碱性细胞滋养层细胞内有强烈的特异性染色。相比之下，位于迷路的嗜碱性细胞滋养层未染色。随后的实验使用凝胶电泳和免疫印迹分析来比较人胎盘和血清中的PSβG与大鼠胎盘和血清中的免疫反应性蛋白质。在人绒毛组织和妊娠血清中检测到一组两到三种蛋白质，其表观分子量（Mr）范围为54,000 - 76,000。相比之下，大鼠胎盘显示出一种主要的免疫反应性蛋白质，Mr为120,000，而大鼠血清含有Mr为48,000、64,000和69,000的条带。大鼠基底层组织的外植体培养物分泌了两种具有免疫反应性的[35S]甲硫氨酸标记蛋白质，一种主要的Mr为120,000的物种和一种次要的Mr为76,000的形式，其pI值为4.6 - 5.5；衣霉素抑制了这两种物种的分泌。因此，一种Mr为120,000的糖蛋白似乎是妊娠第15天胎盘大鼠PSβG类似物的主要组织形式和分泌形式。最后，大鼠胎盘中PSβG样蛋白的细胞化学定位显示，从第12天壁内卵黄囊胎盘的巨大滋养层细胞到第15天的基底层细胞滋养层细胞，存在逐渐的妊娠变化。数据表明，妊娠大鼠可能为研究PSβG在妊娠后期的生物学功能提供一个动物模型。
