Kim Hyo Jeong, Ko Myoung Seok, Kim Hong Kyung, Cho Wha Ja, Lee Seon Ho, Lee Byung Ju, Park Jeong Woo
Department of Biological Sciences, University of Ulsan, Ulsan 680-749, Korea.
Biochim Biophys Acta. 2011 Mar;1809(3):184-90. doi: 10.1016/j.bbagrm.2011.01.004. Epub 2011 Feb 2.
Developmentally regulated GTP-binding protein 2 (DRG2) is an evolutionarily conserved GTP-binding protein. DRG2 mRNA expression has been confirmed in many animal and human tissues. DRG2 is thought to play an essential role in the control of cell growth and differentiation. However, transcriptional regulation of DRG2 is largely unknown. To investigate the mechanisms controlling DRG2 expression, we cloned 1509bp of the 5'-flanking sequence of this gene. Deletion analysis showed that the region between -113 and -70 is essential for the basal level expression of the DRG2 gene in K562 human erythroleukemic cells. Mutation of a putative stimulating protein 1 (Sp1) regulatory site located at position -108 resulted in a significant decline in DRG2 promoter activity. Electrophoretic mobility shift assay and chromatin immunoprecipitation analysis revealed that Sp1 binds to this site. Knockdown of Sp1 expression using siRNA inhibited the promoter activation as well as the endogenous DRG2 transcriptional level. Taken together, these results demonstrate that basal expression level of DRG2 is regulated by the Sp1 transcription factor.
发育调控型GTP结合蛋白2（DRG2）是一种在进化上保守的GTP结合蛋白。DRG2 mRNA表达已在许多动物和人体组织中得到证实。DRG2被认为在细胞生长和分化的控制中起重要作用。然而，DRG2的转录调控在很大程度上尚不清楚。为了研究控制DRG2表达的机制，我们克隆了该基因5'侧翼序列的1509bp。缺失分析表明，-113至-70之间的区域对于DRG2基因在K562人红白血病细胞中的基础水平表达至关重要。位于-108位的假定刺激蛋白1（Sp1）调控位点的突变导致DRG2启动子活性显著下降。电泳迁移率变动分析和染色质免疫沉淀分析表明Sp1结合到该位点。使用小干扰RNA（siRNA）敲低Sp1表达可抑制启动子激活以及内源性DRG2转录水平。综上所述，这些结果表明DRG2的基础表达水平受Sp1转录因子调控。
