Egr-1 regulates the transcription of NGX6 gene through a Sp1/Egr-1 overlapping site in the promoter
1 Department of Gastroenterology, Zhuzhou central Hospital, 412007 Zhuzhou, Hunan, China
2 Department of Gastroenterology, Third Affiliated Hospital of Xiangya School of Medicine, Central South University, 410013 Changsha, Hunan, China
3 Department of Digestive Diseases, Hunan Provincial People’s Hospital, 410005 Changsha, Hunan, China
4 Cancer Research Institute, Central South University, 410078 Changsha, Hunan, China
5 Hunan Key laboratory of Nonresolving Inflammation and Cancer, 410013 Changsha, Hunan, China
BMC Molecular Biology 2014, 15:14 doi:10.1186/1471-2199-15-14Published: 16 July 2014
As a novel candidate metastasis suppressor gene, Nasopharyngeal carcinoma-associated gene 6 (NGX6) is involved in cellular growth, cell cycle progression and tumor angiogenesis. Previous studies have shown that NGX6 gene is down-regulated in colorectal cancer (CRC). However, little is known about its transcriptional regulation.
We defined the minimal promoter of NGX6 gene in a 186-bp region (from-86 to +100) through mutation construct methods and luciferase assays. Results from Electrophoretic mobility shift assays (EMSA) and Chromatin immunoprecipitation (ChIP) revealed that Early growth response gene 1 (Egr-1) binds to the Sp1/Egr-1 overlapping site of NGX6 minimal promoter. Overexpression of Egr-1 increased the promoter activity and mRNA level of NGX6 gene; while knock-down of endogenous Egr-1 decreased mRNA expression of NGX6 gene.
These results demonstrate that Egr-1 regulates NGX6 gene transcription through an overlapping Sp1/Egr-1 binding site as a positive regulator of NGX6 gene.