NR ATEN
AU Varela-Nallar,L.; Toledo,E.M.; Larrondo,L.F.; Cabral,A.L.B.; Martins,V.R.; Inestrosa,N.C.
TI Induction of cellular prion protein gene expression by copper in neurons
QU American Journal of Physiology. Cell Physiology 2006 Jan; 290(1): C271-81
PT journal article
AB Prion diseases are caused by the conformational transition of the native alpha-helical cellular prion protein (PrPc) into a beta-sheet pathogenic isoform. However, the normal physiological function of PrPc remains elusive. We report herein that copper induces PrPc expression in primary hippocampal and cortical neurons. PrPc induced by copper has a normal glycosylation pattern, is proteinase K-sensitive and reaches the cell surface attached by a glycosyl phosphatidylinositol anchor. Immunofluorescence analysis revealed that copper induces PrPc levels in the cell surface and in an intracellular compartment that we identified as the Golgi complex. In addition, copper induced the activity of a reporter vector driven by the rat PrPc gene (Prnp) promoter stably transfected into PC12 cells, whereas no effect was observed in glial C6 clones. Also cadmium, but not zinc or manganese, upregulated Prnp promoter activity in PC12 clones. Progressive deletions of the promoter revealed that the region essential for copper modulation contains a putative metal responsive element. Although electrophoretic mobility shift assay demonstrated nuclear protein binding to this element, supershift analysis showed that this is not a binding site for the metal responsive transcription factor-1 (MTF-1). The MTF-1-independent transcriptional activation of Prnp is supported by the lack of Prnp promoter activation by zinc. These findings demonstrate that Prnp expression is upregulated by copper in neuronal cells by an MTF-1-independent mechanism, and suggest a metal-specific modulation of Prnp in neurons.
IN Im Gegensatz zu Zink und Mangan steigern Kupfer und Cadmium in primären Neuronen aus Hippocampus und Hirnrinde die PrPc-Expression und könnten daher durch Steigerung der Empfänglichkeit und Verkürzung der Inkubationszeit als Cofaktoren von TSE wirken.
MH Amyloid/*genetics/*metabolism; Animals; Cells, Cultured; Cerebral Cortex/cytology; Copper/*metabolism/pharmacology; DNA-Binding Proteins/metabolism; Detergents; Gene Expression Regulation/drug effects; Hippocampus/cytology; Homeostasis/physiology; Neurons/cytology/*physiology; Promoter Regions (Genetics)/physiology; Protein Precursors/*genetics/*metabolism; Rats; Rats, Sprague-Dawley; Research Support, Non-U.S. Gov't; Solubility; Transcription Factors/metabolism
AD Facultad de Ciencias Biologicas, P. Universidad Catolica de Chile, Centro de Regulacion Celular y Patologia Joaquin V. Luco, CRCPand MIFAB, Santiago, Chile.
SP englisch
PO USA