Gudeman D M, Nelson S R, Merisko E M
Tissue Cell. 1987;19(1):101-9. doi: 10.1016/0040-8166(87)90061-9.
Protein synthesis was studied in the isolated rat choroid plexus. When the choroid plexus was studied by transmission electron microscopy, membrane-bound structures were often observed in the ventricular space. These structures appear to bud from the apical surface of the epithelial cells. In the present study, we attempted to isolate these membrane-bound cellular fragments from the choroid plexus and to determine their ability to synthesize proteins. The apical fragments (aposomes) were isolated from the choroid plexus by allowing tissue explants to incubate in media (37 degrees C) for 1 h. The tissue was removed and the media, now containing aposomes, was incubated with [S35]methionine (100 microCi). The media was collected and analysed by SDS-PAGE followed by fluorography. Parallel [S35]methionine incubations were done with whole tissue explants. The SDS-PAGE protein derived from the aposomes was similar to the profile derived from the tissue. In addition, proteins detected in CSF had relative molecular weights comparable to the products synthesized by aposomes. These observations suggest that aposomes provide an additional route of entry for proteins into CSF.
在分离出的大鼠脉络丛中对蛋白质合成进行了研究。当通过透射电子显微镜研究脉络丛时，常在脑室空间观察到膜结合结构。这些结构似乎是从上皮细胞的顶端表面芽生而来。在本研究中，我们试图从脉络丛中分离出这些膜结合的细胞碎片，并确定它们合成蛋白质的能力。通过让组织外植体在培养基（37摄氏度）中孵育1小时，从脉络丛中分离出顶端碎片（顶体）。去除组织，将现在含有顶体的培养基与[35S]甲硫氨酸（100微居里）一起孵育。收集培养基并通过SDS-PAGE随后进行荧光自显影分析。用整个组织外植体进行平行的[35S]甲硫氨酸孵育。来自顶体的SDS-PAGE蛋白质与来自组织的图谱相似。此外，在脑脊液中检测到的蛋白质的相对分子量与顶体合成的产物相当。这些观察结果表明，顶体为蛋白质进入脑脊液提供了另一条途径。
