Characterization of a repressor element in the promoter region of proprotein convertase 2 (PC2) gene.
The proprotein convertase PC2 is primarily expressed in neuroendocrine cells where it mediates the proteolytic maturation of prohormones and proneuropeptides. We have identified in the upstream sequence of its gene a conserved domain partially homologous to the repressor element RE1/NRSE found in several genes for neuronal proteins. RE1/NRSE binds the silencing transcription factor REST/NRSF, a nuclear protein primarily found in nonneuronal cells. To determine the functionality of the PC2 gene RE1-like sequence (RE1-lk), we examined by electrophoretic mobility shift assays its ability to attach nuclear factors from PC2-expressing and nonexpressing cells. Specific binding factors were mostly detectable in PC2-non-expressing cells. These factors differ from REST/NRSF, as molar excess of competing RE1/NRSE could not prevent their binding to RE1-lk. Reciprocally, molar excess of RE1-lk could not prevent the binding of RE1/NRSE to the DNA-binding domain of a recombinant REST/NRSF. The presence of RE1-lk in cis reduced the ability of the PC2 promoter and the heterologous phosphoglycerate kinase promoter to drive expression of a green fluorescent protein reporter gene in transiently transfected PC2-nonexpressing cells, but not in PC2-expressing cells. These observations suggest that binding of transcription-silencing factors to the RE1-lk element may contribute to repression of the PC2 gene in nonneuroendocrine cells.
Diseases of Aging Centre, Ottawa Health Research Institute, Ottawa Hospital, University of Ottawa, 725 Parkdale Avenue, Ottawa, Ontario K1Y 4K9, Canada. mmbikay@ohri.ca
Majambu
M
Mbikay
Marie-Laure
ML
Raffin-Sanson
Francine
F
Sirois
Luaba
L
Kalenga
Michel
M
Chrétien
Nabil G
NG
Seidah
D020816:Amino Acid Motifs / Q000235:genetics; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D002874:Chromosome Mapping; D004268:DNA-Binding Proteins / Q000235:genetics; D005057:Eukaryotic Cells / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D020868:Gene Silencing / Q000502:physiology; D005809:Genes, Regulator / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D006728:Hormones / Q000096:biosynthesis*; D051379:Mice; D008969:Molecular Sequence Data; D009490:Neurosecretory Systems / Q000201:enzymology*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D045706:Proprotein Convertase 2; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012097:Repressor Proteins / Q000235:genetics*; D013381:Subtilisins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics; D014407:Tumor Cells, Cultured; D000099229:RE1-Silencing Transcription Factor
D004268:DNA-Binding Proteins; D006728:Hormones; D045706:Proprotein Convertase 2; D012333:RNA, Messenger; D012097:Repressor Proteins; D013381:Subtilisins; D014157:Transcription Factors; D000099229:RE1-Silencing Transcription Factor