细胞标志蛋白
肾小球
内质网
免疫标记
足细胞
免疫电镜
细胞生物学
免疫染色
高尔基体
免疫荧光
顶膜
免疫金标记
生物
肾
化学
病理
上皮
解剖
超微结构
抗体
免疫组织化学
医学
免疫学
内分泌学
蛋白尿
作者
Eva Schnabel,Gerhard Dekan,Aaro Miettinen,Farquhar Mg
出处
期刊:PubMed
日期:1989-04-01
卷期号:48 (2): 313-26
被引量:56
摘要
The appearance and distribution of podocalyxin on the glomerular epithelium (podocytes) during glomerular development was determined in the newborn rat kidney using specific monoclonal and affinity-purified polyclonal antibodies. Kidneys from 2-day-old rats were perfusion-fixed and processed for immunofluorescence or immunoperoxidase localization or immunogold labeling on ultrathin frozen sections. Podocalyxin first appeared on the apical surfaces of the presumptive podocytes of the S-shaped body above the level of the junctional complexes that connect the cells at this stage. The latter consist of a shallow occluding zonule and a deeper adhering zonule. Early in the capillary loop stage, when the urinary spaces open and the junctional complexes migrate from the apex to the base of the cells, labeling for podocalyxin extended along the lateral plasmalemma above the migrating junctions. In the maturing glomerulus when the foot processes form and the occluding and adhering junctions give way to developing slit diaphragms, podocalyxin was found along all newly-opened surfaces above the occluding junctions or slit membranes. No labeling was found below the latter. Podocalyxin was also detected intracellularly throughout the entire exocytotic pathway--i.e., in the rough endoplasmic reticulum and perinuclear cisternae, in Golgi cisternae and associated vesicles, and in carrier vesicles presumably en route to the cell surface. It is concluded that 1) podocalyxin is synthesized at a high rate in the differentiating podocyte; 2) its distribution is restricted to the apical plus lateral plasmalemmal domain facing the urinary spaces above the migrating junctions; 3) its time of appearance and distribution during glomerular development are identical to that reported earlier for epithelial polyanion; and 4) its synthesis and insertion into the podocyte plasmalemma is closely coupled to the development of the foot processes and filtration slits.
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