Open AccessSp1 and Sp3 regulate basal transcription of the human APOBEC3G gene
Author(s) -
Heide Muckenfuß,
Julia K. Kaiser,
Erika Krebil,
Marion Battenberg,
Christina Schwer,
Klaus Cichutek,
Carsten Münk,
Egbert Flory
Publication year - 2007
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/gkm340
Subject(s) - biology , promoter , chromatin immunoprecipitation , microbiology and biotechnology , reporter gene , transcription (linguistics) , transcriptional regulation , cytidine deaminase , electrophoretic mobility shift assay , transcription factor , response element , gene , luciferase , gene expression , genetics , transfection , linguistics , philosophy
APOBEC3G (A3G), a member of the recently discovered family of human cytidine deaminases, is expressed in peripheral blood lymphocytes and has been shown to be active against HIV-1 and other retroviruses. To gain new insights into the transcriptional regulation of this restriction factor, we cloned and characterized the promoter region of A3G. Transcriptional start sites were identified by 5'-rapid amplification of cDNA ends analysis. Luciferase reporter assays demonstrated that a 1025 bp A3G promoter sequence (from -959 to +66 relative to the major transcriptional start site) displayed constitutive promoter activity. In T cells, the A3G promoter was not inducible by mitogenic stimulation, interferon treatment or expression of HIV-1 proteins. Using a series of 5' deletion promoter constructs in luciferase reporter assays, we identified a 180 bp region that was sufficient for full promoter activity. Transcriptional activity of this A3G core promoter was dependent on a GC-box (located at position -87/-78 relative to the major transcriptional start site) and was abolished after mutation of this DNA element. Electrophoretic mobility shift assays and chromatin immunoprecipitation assays demonstrated that the identified GC-box represented a binding site for the ubiquitous transcription factors specificity protein (Sp) 1 and Sp3.