title: P300 regulates the human RLIP76 promoter activity and gene expression.
abstract: A 76-kDa Ral-interacting protein (RLIP76) has been implicated in the pathogenesis of cancer and diabetes. It is often over expressed in human malignant cell lines and human tumor samples and has been associated with metastasis and chemoresistance. RLIP76 homozygous knockout mice exhibit increased insulin sensitivity, hypoglycemia, and hypolipidemia, and resist cancer development. Little is known about the mechanism by which the expression of RLIP76 is regulated. In the present study, we functionally characterized the RLIP76 promoter using deletion mapping and mutational analysis to investigate the regulation of RLIP76 transcription. We have identified the promoter regions important for RLIP76 transcription, including a strong cis-activating element in the proximal promoter containing overlapping consensus cMYB and cETS binding sites. Transcription factor cMYB and the coactivator p300 associated with RLIP76 gene promoter as shown by CHIP assay. Knockdown of p300 in HEK293 cells reduced the activity of the promoter fragment containing wild type cMYB/cETS binding site in comparison to that with deleted or mutated cMYB/cETS binding site. Knockdown of p300 also decreased the RLIP76 expression as indicated by immunoblotting, immunocytochemistry and flow cytometry analysis. Thus, we report for the first time that p300 associates with the RLIP76 promoter via an overlapping cMYB and cETS binding site and regulates RLIP76 promoter activity and its expression.
authors: Department of Molecular Biology & Immunology, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
authors: Archana
authors: A
authors: Sehrawat
authors: Sushma
authors: S
authors: Yadav
authors: Yogesh C
authors: YC
authors: Awasthi
authors: Alakananda
authors: A
authors: Basu
authors: Charles
authors: C
authors: Warden
authors: Sanjay
authors: S
authors: Awasthi
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D050881:E1A-Associated p300 Protein / Q000502:physiology*; D020690:GTPase-Activating Proteins / Q000235:genetics*; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000235:genetics; D011401:Promoter Regions, Genetic; D050783:Proto-Oncogene Proteins c-ets / Q000378:metabolism; D020598:Proto-Oncogene Proteins c-myb / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D018528:ATP-Binding Cassette Transporters; D020690:GTPase-Activating Proteins; D050783:Proto-Oncogene Proteins c-ets; D020598:Proto-Oncogene Proteins c-myb; C095637:RALBP1 protein, human; D012333:RNA, Messenger; D050881:E1A-Associated p300 Protein