PIN*POINT analysis on the endogenous MnSOD promoter: specific demonstration of Sp1 binding in vivo.
Manganese superoxide dismutase (MnSOD) is a critical antioxidant enzyme that protects against superoxide anion generated as a consequence of normal cellular respiration, as well as during the inflammatory response. By employing dimethyl sulfate in vivo footprinting, we have previously identified ten basal protein binding sites within the MnSOD promoter. On the basis of consensus sequence comparison and in vitro footprinting data, one would predict that Sp1 might occupy five of these binding sites. To address these findings in the context of the nucleoprotein environment, we first utilized chromatin immunoprecipitation (ChIP) to demonstrate the nuclear association of Sp1 with the MnSOD promoter region. To identify the precise location of Sp1 binding, we have modified the original protein position identification with nuclease tail (PIN*POINT) methodology, providing an approach to establish both the identity and binding occupancy of Sp1 in the context of the endogenous MnSOD promoter. These data, coupled with site-directed mutagenesis, demonstrate the functional importance of two of the Sp1 binding sites in the stimulus-specific regulation of MnSOD gene expression. We feel that the combination of ChIP and PIN*POINT analysis allows unequivocal identification and localization of protein/DNA interactions in vivo, specifically the demonstration of Sp1 with the MnSOD promoter.
Kuo
Shiuhyang
S
Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida 32610, USA.
Chokas
Ann L
AL
Rogers
Richard J
RJ
Nick
Harry S
HS
D000818:Animals; D001483:Base Sequence / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D002478:Cells, Cultured; D018983:DNA Footprinting / Q000379:methods*; D004268:DNA-Binding Proteins / Q000235:genetics*; D004847:Epithelial Cells / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000235:genetics; D007249:Inflammation / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed / Q000235:genetics; D009154:Mutation / Q000235:genetics; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic / Q000235:genetics*; D051381:Rats; D016329:Sp1 Transcription Factor / Q000235:genetics*; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; D016329:Sp1 Transcription Factor; D013482:Superoxide Dismutase