title: Genomic organization and promoter cloning of the human X11α gene APBA1.
abstract: X11α is a brain specific multi-modular protein that interacts with the Alzheimer's disease amyloid precursor protein (APP). Aggregation of amyloid-β peptide (Aβ), an APP cleavage product, is believed to be central to the pathogenesis of Alzheimer's disease. Recently, overexpression of X11α has been shown to reduce Aβ generation and to ameliorate memory deficit in a transgenic mouse model of Alzheimer's disease. Therefore, manipulating the expression level of X11α may provide a novel route for the treatment of Alzheimer's disease. Human X11α is encoded by the gene APBA1. As evidence suggests that X11α expression can be regulated at transcription level, we have determined the gene structure and cloned the promoter of APBA1. APBA1 spans over 244 kb on chromosome 9 and is composed of 13 exons and has multiple transcription start sites. A putative APBA1 promoter has been identified upstream of exon 1 and functional analysis revealed that this is highly active in neurons. By deletion analysis, the minimal promoter was found to be located between -224 and +14, a GC-rich region that contains a functional Sp3 binding site. In neurons, overexpression of Sp3 stimulates the APBA1 promoter while an Sp3 inhibitor suppresses the promoter activity. Moreover, inhibition of Sp3 reduces endogenous X11α expression and promotes the generation of Aβ. Our findings reveal that Sp3 play an essential role in APBA1 transcription.
authors.affiliation: Biochemistry Program, School Life Sciences, The Chinese University of Hong Kong , Shatin, New Territories, Hong Kong SAR.
authors.forename: Ka-Ho
authors.initials: KH
authors.lastname: Chai
authors.forename: Declan M
authors.initials: DM
authors.lastname: McLoughlin
authors.forename: Ting Fung
authors.initials: TF
authors.lastname: Chan
authors.forename: Ho Yin Edwin
authors.initials: HY
authors.lastname: Chan
authors.forename: Kwok-Fai
authors.initials: KF
authors.lastname: Lau
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D003001:Cloning, Molecular; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D005091:Exons / Q000235:genetics*; D023281:Genomics; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D024363:Transcription Initiation Site
chemical_list: C079091:APBA1 protein, human; D048868:Adaptor Proteins, Signal Transducing; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D008156:Luciferases