Zahradka P, Yau L
Department of Physiology, St. Boniface General Hospital Research Centre, University of Manitoba, Winnipeg, Canada.
Mol Cell Biochem. 1994 Sep;138(1-2):91-8. doi: 10.1007/BF00928448.
Gene expression can be defined as the conversion of information existing in a molecule of DNA into a mature RNA or protein product and each step in the process, which requires the concerted action of several macromolecules for completion, may be perturbed by the post-translational modification of specific proteins with ADP-ribose. The participation of poly(ADP-ribose) in the regulation of transcription initiation was examined using cell-free systems for both ribosomal RNA and ribosomal proteins. The presence or absence of poly(ADP-ribose) polymerase did not influence the transcription process. Similarly, under conditions optimal for poly(ADP-ribose) polymerase activity, no change in transcription was observed. A direct contribution of poly(ADP-ribosyl)ation to gene transcription thus could not be detected. In contrast, the addition of 3-aminobenzamide to quiescent hepatoma cells treated with insulin inhibited the stimulation of rRNA synthesis. The high concentrations necessary for this effect suggest that a mono(ADP-ribosyl)ation event participates in the cellular action of insulin. A role in the signal transduction pathway leading to activation of rRNA gene expression has been proposed.
基因表达可定义为存在于DNA分子中的信息转化为成熟的RNA或蛋白质产物，该过程中的每一步都需要几种大分子协同作用才能完成，而这可能会受到特定蛋白质与ADP-核糖的翻译后修饰的干扰。使用针对核糖体RNA和核糖体蛋白的无细胞系统研究了聚（ADP-核糖）在转录起始调控中的作用。聚（ADP-核糖）聚合酶的存在与否不影响转录过程。同样，在聚（ADP-核糖）聚合酶活性最佳的条件下，未观察到转录变化。因此，未检测到聚（ADP-核糖基）化对基因转录的直接作用。相反，向用胰岛素处理的静止肝癌细胞中添加3-氨基苯甲酰胺会抑制rRNA合成的刺激。产生这种效应所需的高浓度表明单（ADP-核糖基）化事件参与了胰岛素的细胞作用。有人提出它在导致rRNA基因表达激活的信号转导途径中起作用。
