Kirch H C, Flaswinkel S, Rumpf H, Brockmann D, Esche H
Institute of Molecular Biology (Cancer Research), University of Essen, Medical School, Germany.
Oncogene. 1999 Apr 29;18(17):2728-38. doi: 10.1038/sj.onc.1202626.
Transcriptional control of p53 expression participates in the generation of appropriate levels of active p53 in response to mitogenic stimulation. This prompted us to study the role of a putative AP-1 and a NF-kappaB motif in the human p53 promoter for transcriptional regulation. We show that mutation of the AP-1 or the NF-kappaB motif abolishes transcription from the human p53 promoter in HeLa, HepG2 and adenovirus type 5 E1-transformed 293 cells. In comparison, mutation of the previously characterized Myc/Max/USF binding site in the human p53 promoter reduces the transcription rate fivefold. The AP-1 motif in the human p53 promoter binds c-Fos and c-Jun and the NF-kappaB motif binds p50(NF-kappaB) and p65RelA. The cooperative nature of transcriptional activation by these factors was documented by repression of c-fos or NF-kappaB1 translation: Pretreatment of the cells with a c-fos or p50(NF-kappaB1) antisense oligonucleotide suppresses transcription from the human p53 promoter completely. In addition, we show that (a) the level of endogenous p53 mRNA and (b) transcription from the strictly p53-dependent human mdm2 promoter are reduced in the presence of c-fos, c-jun, p50(NF-kappaB1), p65RelA or c-myc antisense oligonucleotides, underscoring the importance of these transcription factors for the expression of functional p53.
p53表达的转录调控参与了在有丝分裂原刺激下产生适当水平的活性p53。这促使我们研究人p53启动子中一个假定的AP-1和一个NF-κB基序在转录调控中的作用。我们发现，AP-1或NF-κB基序的突变会消除HeLa、HepG2和腺病毒5型E1转化的293细胞中人p53启动子的转录。相比之下，人p53启动子中先前鉴定的Myc/Max/USF结合位点的突变会使转录速率降低五倍。人p53启动子中的AP-1基序结合c-Fos和c-Jun，NF-κB基序结合p50(NF-κB)和p65RelA。这些因子转录激活的协同性质通过抑制c-fos或NF-κB1的翻译得以证明：用c-fos或p50(NF-κB1)反义寡核苷酸预处理细胞可完全抑制人p53启动子的转录。此外，我们还发现，(a)在存在c-fos、c-jun、p50(NF-κB1)、p65RelA或c-myc反义寡核苷酸的情况下，内源性p53 mRNA的水平和(b)严格依赖p53的人mdm2启动子的转录会降低，这突出了这些转录因子对功能性p53表达的重要性。
