Increased AP-1 DNA binding activity in PC12 cells treated with lead.
The possibility that the mechanism of lead neurotoxicity may be at the level of transcription was investigated in PC12 cells. In electrophoretic mobility gel shift assays Pb2+ was found to increase activator protein-1 complex (AP-1) DNA binding activity in PC12 cells; the increase was time- and concentration-dependent. Exposure to Pb2+ also resulted in an increase in AP-1-driven transcription in cerebellar granule cells transfected with a luciferase gene reporter construct. The increase in AP-1 DNA binding activity by Pb2+ required protein synthesis. The increase was mediated by protein kinase C because depletion of protein kinase C and an inhibitor of protein kinase C prevented the increase in AP-1 DNA binding activity by Pb2+. Fra-2 and JunD were found in supershift assays to be the major components of the AP-1 that was increased by Pb2+. In summary, our studies indicate that Pb2+ increases AP-1 DNA binding activity in PC12 cells by a pathway that requires protein kinase C and new protein synthesis.
Chakraborti
T
T
Department of Neurology, Johns Hopkins University School of Public Health and Hygiene and Kennedy Krieger Research Institute, Baltimore, Maryland 21205, USA.
Kim
K A
KA
Goldstein
G G
GG
Bressler
J P
JP
D000818:Animals; D002531:Cerebellum / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D016762:Genes, fos; D016758:Genes, jun; D007700:Kinetics; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D016716:PC12 Cells / Q000187:drug effects* / Q000378:metabolism*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D014176:Protein Biosynthesis; D011493:Protein Kinase C / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D009942:Organometallic Compounds; D011500:Protein Synthesis Inhibitors; D018808:Transcription Factor AP-1; D015240:Phorbol 12,13-Dibutyrate; D004247:DNA; D011493:Protein Kinase C; C008261:lead acetate