The Structure and Function of Perinucleolar Compartment

我们的长期目标是了解PNC的结构和功能及其在恶性肿瘤中的作用。这个 核周间隔(PNC)是一种多组分的无膜结合的核亚结构 定位于核仁外围。我们发现它在体外恶性转化中是独一无二的 在活体内。PNC富含新合成的RNA和主要的RNA结合蛋白 与PolII RNA加工有关。我们的初步发现表明，与PNC相关的RNA位于 与一些已知的PolII RNA结合蛋白形成相同的复合体。这些新颖的络合物并不是 由于PTB-MRP RNA相互作用也可以在没有PNC的正常细胞中检测到，因此仅限于PNC。 然而，在癌变过程中，这些复合体的水平或调节可能会发生变化，导致 这些络合物在PNC中成核。这些发现导致了我们的工作模式，在这种模式下，PNC 与和可能代表新的分子络合物的变化有关，这些分子络合物涉及 新合成的PolIII核糖核酸在恶性肿瘤中的代谢。该提案的目标是开始测试 这一假说是通过使用RNase MRP RNA(RNase MRP RNA之一)识别和初步表征这些新的RNP来实现的 PNC的真正组成部分)作为第一个例子，并通过开始解决功能性 使用细胞生物学方法将这些RNPs与PNC联系起来。因为人们对此了解甚少 PolIII小非编码RNA的转录后处理和调控，解决 新的RNPs不仅对理解PNC的结构和功能具有重要意义，而且还应该揭示 参与这些功能RNA转录后调控的新机制。

Our long-term goal is to understand the structure and function of the PNC and its roles in malignancy. The perinucleolar compartment (PNC) is a multicomponent non-membrane bound nuclear substructure that localizes to the nucleolar periphery. We have found it to be unique to malignant transformation both in vitro and in vivo. The PNC is enriched with RNA newly synthesized by pol III and RNA binding proteins primarily implicated in pol II RNA processing. Our preliminary findings show that the PNC-associated RNAs are in the same complexes with some of the known pol II RNA binding proteins. These novel complexes are not restricted to the PNC since PTB-MRP RNA interactions can also be detected in normal cells without PNCs. However, the levels or the regulations of these complexes may change during malignancy, leading to the nucleation of these complexes in the PNC. These findings lead to our working model in which the PNC is associated with and may represent changes in novel molecular complexes that are involved in the metabolism of newly synthesized pol III RNA during malignancy. The goal of this proposal is to begin test this hypothesis by identifying and initially characterizing these novel RNPs, using RNase MRP RNA (one of the bona fide components of the PNC) as the first example, and by beginning to address the functional association of these RNPs with the PNC using cell biological approaches. As little is understood regarding the post-transcriptional processing and regulation of the pol III small non-coding RNAs, the solution of the novel RNPs is not only important for the understanding of PNC structure and function, but should also reveal a novel mechanism involved in the post-transcriptional regulation of these functional RNAs.