Nutritional Regulation of hnRNP-E1 and Related Genes

描述（由申请人提供）：本提案侧重于以前未被认识到的潜在强大作用，即营养不足可能会改变异质核糖核蛋白E1 （hnRNP-E1）的表达和功能。HnRNP-E1结合多种具有常见c/s元素的RNA，包括人乳头瘤病毒（HPV）基因组中参与HPV病毒衣壳蛋白合成的RNA。我们的主要假设是，在叶酸缺乏中积累的细胞内同型半胱氨酸通过翻译后特异性修饰使hnRNP-E1衍生，将同型半胱氨酸衍生的hnRNP-E1转化为高亲和力的rna结合蛋白，该蛋白上调自身并通过调节mRNA在转录后水平调节宿主其他蛋白质的表达。我们将通过传统的分析方法研究hnRNP-E1蛋白的共价修饰，并通过我们实验室最近建立的方法研究hnRNP-E1在叶酸缺乏小鼠中增殖的宫颈癌异种移植物中翻译自调节的机制。我们还将使用同型半胱氨酸衍生的hnRNP-E1作为钩，以捞出、扩增、表征和分类尚未发现的RNA和可能在叶酸缺乏细胞中受到调节的常见RNA c/s元素。此外，我们将研究同型半胱氨酸衍生的hnRNP-E1在低叶酸条件下增殖的恶性前HPV感染角化细胞中抑制HPV病毒衣壳蛋白生成的机制。这是很重要的，因为对HPV病毒颗粒中主要（L1）和次要（L2）病毒衣壳蛋白结合的干扰可以深刻影响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。这些研究揭示了一种常见的营养缺乏可以深刻诱导一种关键的多功能rna结合蛋白的表观遗传翻译后变化的机制，这种变化反过来可以影响许多其他参与细胞增殖、分化和凋亡的关键蛋白的转录后调控和表达。如果营养确实可以影响产生真正的感染性HPV病毒颗粒的能力，这可以为未来的研究开辟领域，研究营养在调节HPV传染性和HPV感染细胞的恶性转化中的作用。

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.