Yang X, Hill K E, Maguire M J, Burk R F
Division of Gastroenterology, Department of Medicine and Clinical Nutrition Research Unit, Medical Center North C2104, Vanderbilt University School of Medicine, Nashville, TN 37232-2279, USA.
Biochim Biophys Acta. 2000 May 1;1474(3):390-6. doi: 10.1016/s0304-4165(00)00035-0.
Selenoprotein P is an extracellular protein that has been postulated to have an oxidant defense function. It has survival-promoting properties for cultured neurons and its mRNA is present in the brain. This study sought to determine the primary structure of rat brain selenoprotein P and to assess its production by cultured brain cells. The cDNA of selenoprotein P was isolated from a rat brain cDNA library and was found to encode the same peptide sequence as rat liver cDNA. Thus the primary structure of brain selenoprotein P is the same as selenoprotein P from liver. Astrocytes and a cerebellar granule cell preparation (CGC) were obtained from rat brains and established in culture. The CGC was estimated to contain up to 5% glial cells. Both preparations were shown to contain selenoprotein P mRNA. During incubation with (75)Se-labeled selenite, both cell preparations secreted a (75)Se-labeled protein into the medium that corresponded in size to selenoprotein P. Also, the (75)Se-labeled protein could be precipitated from both media with an antiserum to selenoprotein P. This shows that astrocytes and the CGC secrete selenoprotein P. Selenoprotein P is made in the brain and may have an oxidant defense function there.
硒蛋白P是一种细胞外蛋白，据推测具有抗氧化防御功能。它对培养的神经元具有促进存活的特性，其信使核糖核酸存在于大脑中。本研究旨在确定大鼠脑硒蛋白P的一级结构，并评估其在培养的脑细胞中的产生情况。从大鼠脑cDNA文库中分离出硒蛋白P的cDNA，发现其编码的肽序列与大鼠肝脏cDNA相同。因此，脑硒蛋白P的一级结构与肝脏中的硒蛋白P相同。从大鼠脑中获取星形胶质细胞和小脑颗粒细胞制剂（CGC）并进行培养。估计CGC中含有高达5%的神经胶质细胞。两种制剂均显示含有硒蛋白P信使核糖核酸。在用（75）Se标记的亚硒酸盐孵育期间，两种细胞制剂都向培养基中分泌了一种大小与硒蛋白P相对应的（75）Se标记蛋白。此外，（75）Se标记蛋白可以用抗硒蛋白P血清从两种培养基中沉淀出来。这表明星形胶质细胞和CGC分泌硒蛋白P。硒蛋白P在大脑中合成，可能在那里具有抗氧化防御功能。
