Structure and dynamics of enterovirus IRES-ribosome complexes

肠道病毒（例如脊髓灰质炎病毒、鼻病毒、柯萨奇病毒）包括一组不同的人类和动物病原体，据估计，这些病原体每年一起引起超过10亿例感染。一旦进入宿主细胞，它们的正义单链RNA基因组直接翻译产生病毒多蛋白。感染周期中的一个关键事件是募集宿主核糖体以启动翻译。这通过基因组的5'非翻译区中的内部核糖体进入位点（IRES）发生。肠道病毒1型IRES长约450 nt，分为5个结构域，与反式作用蛋白因子（ITAF）相互作用，导致43 S复合物的募集。然而，由于缺乏任何高分辨率的三维结构，我们对这种相互作用网络的理解受到了阻碍。此外，最近在一些肠道病毒中发现了位于主要多蛋白上游的新基因（Lulla et al.，Nat Microbiol，2019）。这利用了位于IRES本身的结构域VI内的替代AUG密码子，但起始位点选择的机制基础尚不清楚。您将研究肠道病毒在各种模型IRES启动的结构和机制基础。这将涉及体外起始的重建、起始复合物的纯化、样品优化、冷冻EM数据收集和处理。您还将使用各种生物物理和生物化学工具研究ITAF和IRES结构域之间的蛋白质RNA相互作用。您将与Lulla实验室（剑桥大学）合作，探索病毒感染细胞中的关键发现。您将加入一个充满活力，多样化和高度支持的培训环境，并拥有三位主管的综合专业知识-核糖体结构生物学和蛋白质-RNA相互作用（Hill和Plevin实验室）和肠道病毒分子生物学（Lulla实验室）。您还将受益于YSBL最先进的cryo-EM基础设施和生物技术设施的分子相互作用实验室。特别鼓励代表性不足群体的候选人申请。

Enteroviruses (e.g. Poliovirus, Rhinovirus, Coxsackievirus) comprise a diverse group of human and animal pathogens, which together are estimated to cause over one billion infections annually. Once inside the host cell, their positive-sense, single-stranded RNA genomes are directly translated to produce the viral polyprotein. A key event in the infection cycle is the recruitment of host ribosomes to initiate translation. This occurs via an internal ribosome entry site (IRES) in the 5' untranslated region of the genome. The enterovirus type 1 IRES is ~450 nt in length and organized into five structured domains, which interact with trans-acting protein factors (ITAFs) leading to recruitment of 43S complexes. However, our understanding of this network of interactions has been hampered by the lack of any high-resolution three-dimensional structures. Furthermore, a new gene has recently been discovered in some enteroviruses, located upstream of the main polyprotein (Lulla et al., Nat Microbiol, 2019). This exploits an alternate AUG codon located within domain VI of the IRES itself, but the mechanistic basis for start-site selection is not understood. You will study the structural and mechanistic basis of enterovirus initiation at a variety of model IRESs. This will involve the reconstitution of initiation in vitro, purification of initiation complexes, sample optimization, cryo-EM data collection and processing. You will also study protein RNA-interactions between ITAFs and IRES domains using a variety of biophysical and biochemical tools. You will explore key findings in virus-infected cells, in collaboration with the Lulla lab (University of Cambridge). You will join a vibrant, diverse and highly supportive training environment with the combined expertise of three supervisors - ribosome structural biology and protein-RNA interactions (Hill and Plevin labs) and Enterovirus molecular biology (Lulla lab). You will also benefit from access to state-of the art cryo-EM infrastructure at YSBL, and the molecular interactions laboratory at the Biology Technology Facility. Candidates from under-represented groups are particularly encouraged to apply.