Nutritional Regulation of hnRNP-E1 and Related Genes

描述(由申请人提供)：这项建议集中在以前没有被认识到的和潜在的强大作用，营养不足可以改变异质性核核糖核蛋白E1(hnRNP-E1)的表达和功能。HnRNP-E1与多种核糖核酸结合，包括人乳头瘤病毒基因组中与HPV病毒衣壳蛋白合成有关的c/S元件。我们的总体假设是，在叶酸缺乏时积累的细胞内同型半胱氨酸通过翻译后特异性修饰而衍生hnRNP-E1，该修饰将同型半胱氨酸衍生的hnRNP-E1转变为高亲和力的RNA结合蛋白，该蛋白上调自身，并通过调节其他蛋白质的mRNA在转录后水平调节它们的表达。我们将用常规的分析方法研究hnRNP-E1蛋白的共价修饰，并用我们实验室最近建立的方法研究在叶酸缺乏的小鼠体内生长的宫颈癌移植瘤中hnRNP-E1的翻译自动调节机制。我们还将使用同型半胱氨酸衍生的hnRNP-E1作为挂钩，用尚未发现的rna和共同的rna c/S-可能在叶酸缺乏细胞中受到调控的元件来筛选、扩增、表征和分类rna。此外，我们将研究同型半胱氨酸衍生的hnRNP-E1可以抑制在低叶酸条件下繁殖的HPV感染前角质形成细胞中HPV病毒衣壳蛋白的产生的机制。这一点意义重大，因为将主要(L1)和次要(L2)病毒衣壳蛋白合并到HPV病毒颗粒中会深刻影响HPV的感染性，并可能最终影响HPV最终将感染细胞转化为癌症的可能性。这些研究可以揭示一种新的机制(S)，通过这种机制，常见的营养缺乏可以深刻地诱导关键的多功能核糖核酸结合蛋白的表观遗传翻译后变化，进而影响参与细胞增殖、分化和凋亡的许多其他关键蛋白质的转录后调控和表达。如果营养确实可以影响产生真正的传染性HPV病毒颗粒的能力，这可能会为未来的研究开辟领域，以研究营养在调节HPV感染性和HPV感染细胞恶性转化中的作用。

DESCRIPTION (provided by applicant): This proposal focuses on a previously unappreciated and potentially powerful role that inadequate nutrition can have to modify the expression and function of heterogeneous nuclear ribonucleoprotein E1 (hnRNP-E1). HnRNP-E1 binds a multitude of RNA with common c/s-elements including those within the genome of human papillomavirus (HPV) that are involved in the synthesis of HPV viral capsid proteins. Our overarching hypothesis is that intracellular homocysteine which accumulates in folate deficiency derivatizes hnRNP-E1 by a post-translational specific modification that transforms homocysteine-derivatized hnRNP-E1 into a high-affinity RNA-binding protein which up-regulates itself and modulates the expression of a host of other proteins at the post-transcriptional level by regulating their mRNA. We will study the covalent modification of hnRNP-E1 protein by conventional analytical methods and the mechanism of translational auto-regulation of hnRNP-E1 in cervical cancer xenografts propagated in folate- deficient mice by methods recently established in our laboratory. We will also use homocysteine-derivatized hnRNP-E1 as a hook to fish out, amplify, characterize, and catalog as yet undiscovered RNA with common RNA c/s-elements that are likely to be regulated in folate-deficient cells. In addition, we will investigate the mechanism whereby homocysteine-derivatized hnRNP-E1 can quench the generation of HPV viral capsid proteins in pre-malignant HPV-infected keratinocytes that are propagated under conditions of low folate. This is significant because perturbation of the incorporation of both the major (L1) and minor (L2) viral capsid proteins into HPV viral particles can profoundly affect both the infectivity of HPV, and may also eventually influence the potential for HPV to eventually transform infected cells into cancer. These studies can uncover new insight into mechanism(s) by which a common nutritional deficiency can profoundly induce an epigenetic posttranslational change of a key multifunctional RNA-binding protein that can, in turn, influence the post-transcriptional regulation and expression of many other critical proteins involved in cell proliferation, differentiation and apoptosis. And if indeed nutrition can influence the capacity to generate authentic infectious HPV viral particles, this could open the field for future studies to investigate the role of nutrition in modulation of HPV-infectivity and malignant transformation of HPV-infected cells.