Transitions: Mechanistic insights into ribosome rescue and quality control in the Archaea

细胞使用一种称为翻译的过程来根据mRNA分子中的密码合成蛋白质。 翻译代码时的错误会造成许多有害影响。 核糖体是翻译mRNA代码和合成蛋白质的细胞纳米机器。 核糖体在不断使用，必须重复使用多次，有两个过程需要这种重复使用。 首先，在一个mRNA的翻译结束后，有一个称为核糖体回收的活跃过程，将核糖体从mRNA中分离出来，以便可以重复使用。 第二，有时核糖体在翻译过程中停滞甚至碰撞，不能自行重新启动;在这种情况下，仍然存在一个主动过程，将mRNA与被破坏的核糖体分离，以便核糖体可以重新使用。 这个研究项目将调查最不了解的生命领域，被称为古生菌，如何完成核糖体的拯救和回收。该项目还将为研究生提供培训，并将巴尔的摩市公立学校的高中生纳入研究。为了进行科学调查，研究小组将使用Haloferax volcano ii，一种嗜盐古菌，适合遗传和生化调查。 在aim1中，研究人员将确定在古细菌中识别停滞核糖体并促进核糖体分裂活性的蛋白质因子。他们将使用遗传和生物化学方法来发现目前在古细菌中未知的新因子。在目标2中，研究人员将确定古细菌中核糖体碰撞的景观。 核糖体碰撞导致称为二体的核糖体二聚体;二体保护片段的深度测序将提供碰撞基序的全基因组表征和测试体内核糖体拯救中感兴趣的新因子的作用的能力。在目标3中，研究人员将确定由停滞的核糖体产生的多肽的蛋白水解靶向机制。这些实验将提供古细菌核糖体相关质量控制（RQC）途径的第一个知识。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Cells use a process called translation to synthesize proteins according to the code in an mRNA molecule. Mistakes in translating the code can cause many deleterious effects. Ribosomes are the cellular nanomachines that translate the mRNA code and synthesize proteins. Ribosomes are in constant use and must be reused many times and there are two processes necessary for this reuse. First, after translation of one mRNA concludes, there is an active process called ribosome recycling that separates the ribosome from the mRNA so that it can be reused. Second, sometimes ribosomes stall or even collide during translation and cannot restart on their own; again in this case there is an active process that separates the mRNA from the disrupted ribosomes so that the ribosomes can be reused. This research project will investigate how the least-understood domain of life, known as the archaea, accomplish ribosome rescue and recycling. The project will also provide training for graduate students and include high school students from the Baltimore City public schools in the research.To do the scientific investigations, the research team will use Haloferax volcanii, a halophilic archaeon that is amenable to genetic and biochemical investigation. In aim 1, the researchers will identify protein factors that recognize stalled ribosomes and promote ribosome splitting activity in archaea. They will use genetic and biochemical approaches to discover novel factors that are currently unknown in the archaea. In aim 2, the researchers will determine the landscape of ribosome collisions in archaea. Ribosome collisions result in ribosome dimers called disomes; deep-sequencing of disome-protected fragments will provide a genome-wide characterization of collision motifs and the ability to test the role of novel factors of interest in ribosome rescue, in vivo. In aim 3, the researchers will identify the mechanisms for proteolytic targeting of polypeptides produced by stalled ribosomes. These experiments will provide first knowledge of Ribosome-associated Quality Control (RQC) pathways in archaea.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.