Mechanism of promoter activity of the beta-amyloid precursor protein gene in different cell lines: identification of a specific 30 bp fragment in the proximal promoter region.
The amyloid beta-protein (Abeta) deposited in brains of Alzheimer's disease (AD) patients is proteolytically derived from a large Abeta precursor protein (APP). APP gene expression patterns in the AD brain region indicate that abnormalities of gene regulation may be important in AD pathology. To understand the contribution of different cell types to APP gene expression, we studied it at four levels: promoter activity (by reporter gene assay of transfected cells), DNA-nuclear protein interaction (by electrophoretic mobility shift assay), RNA message and protein (by northern and western blotting, respectively). APP mRNA and protein expression levels were greater in neuroblastoma and PC12 cells than in glial or cervix epithelial cells. Relative activity among 12 different promoter regions and within single regions varied according to cell type/cell line. An upstream regulatory region containing a GATA-1 site is necessary for activity in PC12 and glial cells but not in neuroblastoma cells. DNA-protein interactions were examined in three distal and one proximal promoter elements in nuclear extracts belonging to neuronal and non-neuronal cells. The proximal promoter region is important for cell line-specific APP gene expression. Characterization of the APP regulatory region's interaction with cell type-specific nuclear factor(s) is important to understand tissue-specific expression of APP seen in AD subjects.
Ge
Yuan-Wen
YW
Laboratory of Molecular Neurogenetics, Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana 46202-4887, USA.
Ghosh
Chandramallika
C
Song
Weihong
W
Maloney
Bryan
B
Lahiri
Debomoy K
DK
D016564:Amyloid beta-Protein Precursor / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001482:Base Composition; D015152:Blotting, Northern / Q000379:methods; D015153:Blotting, Western / Q000379:methods; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004285:Dogs; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D005786:Gene Expression Regulation / Q000502:physiology*; D000882:Haplorhini; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid / Q000502:physiology; D013045:Species Specificity; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection / Q000379:methods
D016564:Amyloid beta-Protein Precursor; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; C494689:Gata1 protein, mouse; C494690:Gata1 protein, rat; D012333:RNA, Messenger; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase