Synthesis and secretion of selenoprotein P by cultured rat astrocytes.
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.
Yang
X
X
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.
Hill
K E
KE
Maguire
M J
MJ
Burk
R F
RF
D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001345:Autoradiography; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D015723:Gene Library; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D012644:Selenium Radioisotopes; D051149:Selenoprotein P; D051140:Selenoproteins
D018076:DNA, Complementary; D011506:Proteins; D012333:RNA, Messenger; D012644:Selenium Radioisotopes; D051149:Selenoprotein P; D051140:Selenoproteins