NSF-BSF: Circular RNAs as a primate-specific mechanism to create proteome diversity

NSF-BSF：环状RNA作为灵长类动物特异性机制来创造蛋白质组多样性

• 批准号: 2221921
• 负责人: Stefan Stamm
• 金额: $ 70.81万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2221921&HistoricalAwards=false
• 关键词: NSF; BSF; Circular; RNAs; primate

Although proteins that make up the body are almost identical between mice and humans, humans have a superior brain. This conundrum raises the question: What is the molecular basis that makes human brains superior to the brains of other species? The major genomic differences between humans and other species are outside the DNA sequences containing the instructions to make proteins. Human DNA has been ‘invaded’ by short fragments, called Alu-elements that now comprise about 10% of our genome. Alu-elements do not contain instructions to make proteins. The Alu element invasion started in primitive monkeys and is most pronounced in humans, chimpanzees and gorillas. The number of Alu elements correlates with brain function via an unclear molecular mechanism. To make proteins, DNA is made into RNA, which is made into proteins. Alu elements promote the formation of a new class of RNAs, called circular RNAs, where the RNA is not linear with a beginning and an end, but circular like a record. Unexpectedly, circular RNAs can be made into proteins. Thus, by promoting circular RNAs, Alu elements could generate new human-specific proteins. These proteins will be identified and their effect on human nerve cells will be tested. The project is a collaboration with an Israeli group. To train the next generation of molecular biologists, undergraduate students will be taught in a two-week RNA biology course that involves theoretical lessons and hands-on experiments at Hebrew University in Jerusalem. The theoretical lessons will be published as free internet videos and as a book.Circular RNAs are a novel class of RNA generated through backsplicing from pre-mRNAs that are strongly expressed in brain. Despite their lack of a cap or ribosomal entry sites, circRNAs can be translated after adenosine to inosine editing in cell culture. Backsplicing is promoted by Alu elements that expanded in the primate lineage. It is possible that the observed correlation between Alu elements and cognitive abilities is due to the formation of Alu-element dependent, primate-specific circular RNAs. The project will test the overall hypothesis that Alu-dependent circular RNAs are translated after AI editing emanating from ADAR enzymes and that the circRNAs encode novel, undiscovered proteins. The project will (a) investigate the molecular mechanism of circRNA translation after adenosine to inosine editing, hypothesizing that inosines promote ribosomal entry. The formation of circRNAs will be (b) mechanistically characterized by determining the factors that influence the competition between linear and circular RNA splicing in the endogenous spliceosome, and by characterizing associated proteins. The functionality of selected circRNAs will be (c) tested in biochemical and cell-based assays, postulating that proteins made from circular RNAs interfere with the multimerization of their linear counterparts. For broader impacts, the USA-Israeli team will organize annual RNA summer schools with theoretical lectures and practical courses at Hebrew University in Jerusalem. The graduate level English RNA lectures will be recorded, subtitled with Spanish, Hebrew and Arabic and posted on YouTube. They will be accompanied by a book: ‘RNA biology: A practical approach’ to train the next generation of RNA biologists.This collaborative US/Israel project is supported by the US National Science Foundation and the Israeli Binational Science Foundation.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.

尽管组成身体的蛋白质在小鼠和人类之间几乎相同，但人类的大脑具有优越的大脑。这个难题提出了一个问题：什么是使人类大脑优于其他物种的大脑的分子基础？人与其他物种之间的主要基因组差异在于包含制造蛋白质指令的DNA序列之外。人DNA已被短片段“入侵”，称为Alu元素，现在完成了我们约10％的基因组。 ALU元素不包含制造蛋白质的说明。 Alu元素感染始于原始猴子，在人类，黑猩猩和大猩猩中最为明显。 ALU元素的数量通过不清的分子机制与脑功能相关。为了制作蛋白质，将DNA制成成RNA，并将其制成蛋白质。 Alu元素促进了新的RNA类别的形成，称为圆形RNA，其中RNA不是线性的，而不是开始的，而是像记录一样圆形的。出乎意料的是，可以将圆形RNA制成蛋白质。通过促进圆形RNA，ALU元素可以产生新的人类特异性蛋白质。这些蛋白质将被鉴定，并将测试它们对人神经细胞的影响。该项目是与以色列团体的合作。为了培训下一代分子生物学家，将在为期两周的RNA生物学课程中教授本科生，该课程涉及耶路撒冷希伯来大学的理论课程和动手实验。理论课程将以免费的互联网视频和书籍出版。CircularRNA是通过从前MRNA的后置产生的一类新颖的RNA，在大脑中强烈表达。尽管缺乏帽子或核糖体进入位点，但在腺苷后可以将CircrNA翻译成细胞培养中的插入式编辑。反复序列是由在主要谱系中扩展的ALU元素促进的。观察到的Alu元素与认知能力之间观察到的相关性可能是由于形成了依赖ALU元素的原发性圆形RNA。该项目将检验总体假设，即ADAR酶发出AI编辑后翻译Alu依赖性圆形RNA，并且CIRCRNA编码了小说，未发现的蛋白质。该项目将（a）研究腺苷对插入编辑后circRNA翻译的分子机制，假设内氨酸促进核糖体进入。 CIRCRNA的形成将是（b）通过确定影响内源性剪接体中线性和圆形RNA剪接之间竞争的因素，并通过表征相关蛋白质来进行机械表征。选定的CIRCRNA的功能将在生化和基于细胞的测定中进行（C）测试，并假定由圆形RNAS干扰其线性对应物的多层化制成的蛋白质。为了获得更广泛的影响，美国 - 以色列团队将在耶路撒冷希伯来大学组织年度RNA暑期学校。将录制研究生级的英语RNA讲座，并用西班牙语，希伯来语和阿拉伯语字幕，并在YouTube上发布。他们将伴随一本书：“ RNA生物学：一种实用方法”，以培训下一代RNA生物学家。该协作的美国/以色列项目得到了美国国家科学基金会和以色列绑定科学基金会的支持。该奖项反映了NSF的法定任务，并通过评估基金会的智能效果和广泛的范围来表现出值得评估的支持。