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.
Mbikay
Majambu
M
Diseases of Aging Centre, Ottawa Health Research Institute, Ottawa Hospital, University of Ottawa, 725 Parkdale Avenue, Ottawa, Ontario K1Y 4K9, Canada. mmbikay@ohri.ca
Raffin-Sanson
Marie-Laure
ML
Sirois
Francine
F
Kalenga
Luaba
L
Chrétien
Michel
M
Seidah
Nabil G
NG
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