Fischer Martin, Steiner Lydia, Engeland Kurt
a Molecular Oncology; Medical School ; University of Leipzig ; Leipzig , Germany.
Cell Cycle. 2014;13(19):3037-58. doi: 10.4161/15384101.2014.949083.
The predominant function of the tumor suppressor p53 is transcriptional regulation. It is generally accepted that p53-dependent transcriptional activation occurs by binding to a specific recognition site in promoters of target genes. Additionally, several models for p53-dependent transcriptional repression have been postulated. Here, we evaluate these models based on a computational meta-analysis of genome-wide data. Surprisingly, several major models of p53-dependent gene regulation are implausible. Meta-analysis of large-scale data is unable to confirm reports on directly repressed p53 target genes and falsifies models of direct repression. This notion is supported by experimental re-analysis of representative genes reported as directly repressed by p53. Therefore, p53 is not a direct repressor of transcription, but solely activates its target genes. Moreover, models based on interference of p53 with activating transcription factors as well as models based on the function of ncRNAs are also not supported by the meta-analysis. As an alternative to models of direct repression, the meta-analysis leads to the conclusion that p53 represses transcription indirectly by activation of the p53-p21-DREAM/RB pathway.
肿瘤抑制因子p53的主要功能是转录调控。人们普遍认为,p53依赖的转录激活是通过与靶基因启动子中的特定识别位点结合来实现的。此外,还提出了几种p53依赖的转录抑制模型。在此,我们基于全基因组数据的计算荟萃分析来评估这些模型。令人惊讶的是,几种主要的p53依赖基因调控模型似乎并不合理。大规模数据的荟萃分析无法证实关于p53直接抑制靶基因的报道,并证伪了直接抑制模型。对报道为被p53直接抑制的代表性基因进行的实验重新分析支持了这一观点。因此,p53不是转录的直接抑制因子,而仅激活其靶基因。此外,基于p53对激活转录因子的干扰的模型以及基于非编码RNA功能的模型也未得到荟萃分析的支持。作为直接抑制模型的替代方案,荟萃分析得出结论,p53通过激活p53-p21-DREAM/RB途径间接抑制转录。