title: Identification of PARP-1 as one of the transcription factors binding to the repressor element in the promoter region of COX-2.
abstract: Cyclooxygenase-2 (COX-2) plays important roles in the development of many disease conditions, including pancreatic β-cell dysfunction. Although the processes involved in the transcriptional regulation of COX-2 are well documented, some key elements, especially inhibitory elements, are still unknown. In our previous study, we identified a novel repressor element located in promoter region of mouse COX-2. In this study, we isolated several DNA-binding proteins from NIT-1 cells via DNA affinity chromatography; the most prominent among these proteins was poly (ADP-ribose) polymerase-1 (PARP-1). In this study, gel-supershift assays and chromatin immunoprecipitation assays showed that PARP-1 can bind to the inhibitory element -655/-632 in the promoter region of mouse COX-2 both in vitro and in vivo. Furthermore, overexpression of PARP-1 significantly inhibited promoter activity and decreased COX-2 expression. Conversely, repression of PARP-1 by RNAi upregulated COX-2 expression. These data suggest that PARP-1 plays an important role in the regulation of COX-2 expression via binding to the inhibitory element. Collectively, our findings provide new important information on the transcriptional regulation of COX-2 in pancreatic β-cells.
authors.affiliation: Key Laboratory of Human Functional Genomics of Jiangsu Province, Clinical Diabetes Centre of Jiangsu Province, Nanjing Medical University, 140 Hanzhong Road, Nanjing 210029, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lin
authors.forename: Xinyi
authors.initials: X
authors.lastname: Tang
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Zhu
authors.forename: Tingting
authors.initials: T
authors.lastname: Shu
authors.forename: Xiao
authors.initials: X
authors.lastname: Han
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism; D005786:Gene Expression Regulation; D051379:Mice; D008969:Molecular Sequence Data; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D034622:RNA Interference
chemical_list: D004268:DNA-Binding Proteins; D051546:Cyclooxygenase 2; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases