Ribosome remodeling as a mechanism of translational control during stress

项目总结 翻译调控是细胞内主要的基因表达调控机制之一。 调节失调会导致许多人类疾病。核糖体一般被视为构成分子。 然而，发生蛋白质合成的机器，这种观点最近受到了挑战，支持 核糖体特化假说，开辟了全新的研究领域。该项目将调查 以利什曼原虫为模式生物的原生动物核糖体特化的基本概念。在……里面 与其他真核生物不同，包括利什曼原虫在内的锥虫是单细胞生物，它们的 基因表达的调控主要是在mRNA翻译过程中实现的。因此，这种原生动物代表着一种 研究核糖体特化在mRNA翻译调控中的作用的优秀模式生物。 包括温度、pH、营养条件在内的环境在基因表达调控中起着很大的作用， 然而，人们对翻译过程中参与调控的分子因子知之甚少 环境胁迫与寄主的变化。众所周知，翻译在高温期间受到整体抑制。 然而，令人震惊的是，一些mRNA逃脱了翻译抑制，它们的翻译得到了增强。翻译： 编码参与应激反应的蛋白质的mrna对利什曼原虫的应对能力非常重要。 然而，对于压力、其分化和生存，人们还不太清楚热诱导的mrna是如何逃逸的。 热应激过程中的整体翻译抑制。这个项目是基于核糖体的假设 构图在热应激期间经历了实质性的变化，以促进子集的有效翻译 编码参与应激反应的蛋白质的mRNAs。建议的研究将在以下地点提供新资料 几个不同的水平：(目标1)它将在全基因组范围内识别被主动翻译的mRNAs的子集 热应激期间；(目标2)揭示热激期间利什曼原虫核糖体组成的变化 压力；最后，(目标3)它将使用CRISPR/Cas9基因敲除筛选哪些蛋白质确实促进 热诱导转录本的选择性翻译及其在利什曼原虫生活史中的作用。这 综合多学科方法将首次揭示成绩单如何选择性地依赖于特定的 核糖体成分/调节因子在原生动物应激过程中的高效翻译及其作用 在利什曼原虫的分化中。

PROJECT SUMMARY Translational control is one of the major gene expression regulation mechanisms in the cell and its dysregulation leads to many human diseases. Ribosomes in general are viewed as constitutive molecular machines where protein synthesis takes place, however, this view has been recently challenged supporting the hypothesis of ribosome specialization and opening completely new field of research. This project will investigate the fundamental concept of ribosome specialization in protozoa using Leishmania as a model organism. In contrast to other eukaryotes, trypanosomatids including Leishmania species are unicellular organisms and their control of gene expression is mostly achieved during mRNA translation. Therefore, this protozoan represents an excellent model organism to study the role of ribosome specialization in mRNA translation regulation. Environment including temperature, pH, nutrition conditions plays a big role in gene expression regulation, however, it is poorly understood what molecular players are involved in the regulation of translation during environmental stresses and change of host. It is known that translation is globally repressed during the heat shock, however, some mRNAs escape translational repression and their translation is enhanced. Translation of mRNAs encoding for proteins involved in stress response is very important for the Leishmania ability to cope with stress, its differentiation and survival, however, it is not well understood how heat-induced mRNAs escape the global translational repression during the heat stress. This project is based on the hypothesis that ribosome composition undergoes a substantial change during heat stress to promote efficient translation of subset of mRNAs encoding for proteins involved in stress response. The proposed study will provide new information at several different levels: (Aim 1) it will identify on genome-wide scale subset of mRNAs that are actively translated during the heat stress; (Aim 2) it will reveal changes in ribosome composition of Leishmania during the heat stress; and finally, (Aim 3) it will examine using CRISPR/Cas9 knock-out screen what proteins indeed promote selective translation of heat-induced transcripts and what role they play in the life cycle of Leishmania. This comprehensive multidisciplinary approach will reveal for the first time how transcripts selectively rely on specific ribosome components/regulators for their efficient translation during stress in protozoa and establish their role in Leishmania differentiation.