Protein Translation Control of Cytokine Receptors

受体蛋白帮助细胞与环境沟通。这些蛋白质的可用性可以控制在三个阶段，i)编码这些蛋白质的DNA/基因被转化为mRNA/转录产物(转录控制)，ii)在蛋白质合成阶段(翻译控制)，iii)蛋白质合成后的修饰(翻译后修饰)。其中，翻译调控及其在免疫调节等复杂过程中的作用尚未得到充分认识。*合作者J.Dinman(美国马里兰州)最近的研究表明，程序性核糖体框架移位(PRF)是一种翻译控制机制，发生在哺乳动物细胞中。这是令人兴奋的，因为PRF以前只在酵母和病毒转录调控中显示出来。在这种机制中，被称为伪结基序的结构导致核糖体在蛋白质合成过程中向后滑动到mRNA上，导致形成更少的蛋白质。我们使用称为细胞因子的免疫分子，特别是白介素7(IL-7)受体及其IL-7Rα亚单位，来表明PrF可以调节细胞因子受体，并可能在正常免疫系统的发育和功能中发挥作用。白介素7(IL-7)是一种免疫发育所必需的细胞因子，表明严格控制受体和激素水平的重要性。它在T、B细胞和先天淋巴样细胞的发育中起着核心作用。我们在处理IL-7方面拥有成熟的专业知识，并且已经证明IL-7Rα信号对T细胞和B细胞的发育至关重要。*我们关于PrF在IL-7Rα翻译控制中的作用的有希望的初步工作，提出了基本的机制问题，即如何通过翻译控制细胞因子来控制正常免疫系统的发育，这些问题在AIMS中得到了解决。我们的长期目标是解决蛋白质合成控制在调节细胞因子受体可用性方面的重要性。我们假设，细胞因子RNA中的基序提供了在T细胞中调节的蛋白质合成控制。为了验证这一假设，我们将：1)以IL-7Rα为模型，调查细胞因子是如何翻译调控的；2)评估细胞因子的翻译调控是如何调控的；3)评估细胞因子翻译调控的其他机制，如启动。我们将使用先进的分子生物学方法和实验室建立的实验系统来进行这项工作。*这项研究计划的结果将为哺乳动物细胞中一种新的调控形式提供见解，这将有助于在未来开发应用于畜牧业和控制蛋白质生产的新型生物技术，具有重要的学术和经济价值。该计划将帮助培训两名研究生和一名本科生，以促进公平机会，并根据不列颠哥伦比亚省公平和多样性战略计划对代表性不足的群体进行培训。

Receptor proteins help cells communicate with their environment. The availability of these proteins can be controlled at three stages, i) where the DNA/genes coding these proteins get converted to mRNA/transcripts (transcriptional control), ii) at the protein synthesis stage (translational control), iii) modification of proteins after synthesis (post-translational modifications). Of these, translational control and its role in complex processes such as immune regulation is under appreciated. ******Recent work by collaborator J. Dinman (U. Maryland), showed that programmed ribosomal frameshifts (PRF), a mechanism of translational control, occurs in mammalian cells. This is exciting, as PRF had previously only been shown in yeast and virus transcript regulation. In this mechanism, structures called pseudoknot motifs cause the ribosomes to slip backwards on the mRNA during protein synthesis, causing less protein to form. We used immune molecules called cytokines, particularly the Interleukin-7 (IL-7) receptor and its IL-7Rα subunit, to show that PRF can regulate cytokine receptors and may play a role in the development and functioning of a normal immune system. Interleukin-7 (IL-7) is a cytokine essential for immune development which shows the importance of tight control of receptor and hormone levels. It plays central roles in development of T- and B-cells and innate lymphoid cells. We have proven expertise in working with IL-7, and have already shown that IL-7Rα signals are critical for T- and B-cell development. ******Our promising preliminary work on the role of PRF in translational control of IL-7Rα, raises basic mechanistic questions about how the development of a normal immune system is controlled via translational control of cytokines, addressed in the Aims. Our long-term goal is to address the importance of protein synthesis control in tuning cytokine receptor availability. We hypothesize that motifs in cytokine RNAs confer protein synthesis control that is regulated in T cells. To test this hypothesis we will: 1) investigate how cytokines are translationally regulated by PRF, using IL-7Rα as a model; 2) assess how such translational control of cytokines is regulated; 3) evaluate other mechanisms of translational control of cytokines, such as initiation. We will use advanced molecular biology methods and established experimental systems in our lab for this work.******The results of this research program will provide insight into a new form of regulation in mammalian cells, which in the future can help develop applications in animal husbandry and novel biotechnologies to control protein production, and will be of great academic and economic value. This program will help train two graduate students and one undergraduate student recruited to promote equitable opportunity and training for underrepresented groups as per the UBC Equity and Diversity Strategic Plan.