RADIATION INDUCED RNA BINDING PROTEINS

在它们的一生中，细胞必须不断地监测和修复 对他们的DNA造成了损害。产生的自由基和过氧物 在正常生理过程和炎症过程中，以及 环境污染物、紫外线和电离辐射 DNA损伤剂的最常见来源。如果没有被感知到并且 如果修复得当，这种损伤可能会导致恶性转化， 部分通过某些癌基因中特定位置的突变来实现。在……里面 正常的人类细胞，其基因毒性应激反应是相当复杂的。 它包括诱导几个与之相关的基因 具有许多重要的细胞事件，例如细胞周期控制， 信号转导、复制、突变、转录、DNA修复 和病毒激活。我们建议研究该计划的某一方面。 涉及RNA结合诱导的遗传毒性应激反应 特定蛋白质的活性。 我们的初步数据首次证明了RNA结合 DNA损伤可以诱导细胞蛋白质的活性。这 暗示了细胞基因调控的重要意义 在基因毒性应激之后，以及可能参与DNA损伤 识别和修复。这些化合物的诱导结合活性 蛋白质，如先前描述的构成RNA结合蛋白 (RBP)，可以在RNA加工水平上调节基因表达，并 信使核糖核酸稳定性。更重要的是，这些RBP识别特定的RNA 结构，双阀杆环路。可以想象，这样的结构 可能是由部分分离后的新转录形成的 他们的DNA模板。在损伤部位，这些新生细胞的转录 文字记录可能会停滞不前。通过与这些成熟前序列结合， RBP可作为终止子，促进DNA修复的某些方面。 有趣的是，这些RBP识别的RNA结构也是 让人想起HIV-1感染时产生的病毒TAR RNA结构 细胞。在基因中毒后病毒激活的调节中的作用 对于这些RBP来说，压力暴露似乎也是可能的。使用原件 西北印迹法，我们检测到多种RBP在 全核提取液。亲和分离出一种40 kDa的蛋白质 使用特定的RNA低聚体柱进行层析。我们计划 对该蛋白进行测序并分离其cDNA，以确定其 在基因毒性应激反应中的作用。我们还计划研究这一角色 A-18的一个编码RBP的独立分离克隆，由 紫外光，在应激反应中。

Throughout their lives cells have to constantly monitor and repair the damage inflicted on their DNA. Free radicals and peroxides, generated during normal physiological processes and inflammation, as well as environmental pollutants, ultra-violet light, and ionizing radiation are the most common sources of DNA damaging agents. If not sensed and properly repaired, this damage can cause malignant transformation, in part through mutations at specific sites in certain oncogenes. In normal human cells, the genotoxic stress response is rather complex. It includes the induction of several genes that have been associated with a number of important cellular events such as cell cycle control, signal transduction, replication, mutagenesis, transcription, DNA repair and viral activation. We propose to study a particular aspect of the genotoxic stress response involving the induction of RNA-binding activity of specific proteins. Our initial data demonstrated for the first time that RNA-binding activity of cellular proteins can be inducible by DNA damage. This suggested important implications for the regulation of cellular genes after genotoxic stress, as well as possible involvement in DNA damage recognition and repair. The inducible binding activity of these proteins, as previously described constitutive RNA Binding Proteins (RBP), could regulate gene expression at the level of RNA processing and mRNA stability. More importantly, these RBP recognized a specific RNA structure, double stem loop. It is conceivable that such structures could be formed by nascent transcripts after partial separation from their DNA template. At sites of damage, transcription of these nascent transcripts might stall. By binding to these pre-mature sequences, the RBP may act as terminators and facilitate some aspect of DNA repair. Interestingly, the RNA structure recognized by these RBP is also reminiscent of the viral TAR RNA structure generated in HIV-1 infected cells. A role in the regulation of viral activation following genotoxic stress exposure seems also possible for these RBP. Using an original Northwestern blotting approach, we have detected a variety of RBP in whole nuclear extracts. A 40 kDa protein has been isolated by affinity chromatography using a specific RNA oligomer column. We plan to sequence this protein and isolate its cDNA in order to determine its role in the genotoxic stress response. We also plan to study the role of A-18, an independently isolated clone coding for a RBP induced by ultra-violet light, in the stress response.