Role of a novel human-virus chimeric protein generated by upstream translation and genetic overprinting

总结 病原体克服宿主屏障并建立感染的能力是基于 病原体衍生蛋白的表达。为了了解病原体如何对抗宿主 并建立感染，我们需要清楚地了解什么蛋白质是病原体 编码，它们如何发挥作用，以及它们以何种方式对毒力起作用。当前 关于许多威胁生命的病原体的教条是，它们只编码少数蛋白质， 因为它们有限的基因组。RNA病毒，如甲型流感病毒（IAV），就是一个很好的例子 这种范式。在此基础上，我们对病毒生命周期、发病机制和 疾病控制的治疗或预防方法仅限于一小部分已知的 由病毒基因组编码的蛋白质。 我们假设，作为宿主-病毒遗传相互作用的结果，RNA病毒可以产生 嵌合宿主病毒基因在感染过程中被翻译成蛋白质。事实上，IAV， 许多其他高致病性病毒使用短的宿主RNA来引发病毒转录， 产生病毒mRNA。因此，我们进一步假设宿主引物中的起始密码子 序列可以驱动嵌合人病毒编码序列的表达，这一过程 将取决于病毒UTR序列的可翻译性。我们最近的出版物表明， 这种机制的存在，创造了人类病毒蛋白嵌合体， 通过遗传重叠来延伸典型病毒蛋白或新多肽。这种想法是 在一些初步案例研究中，得到了进化分析和功能数据的支持。的 这个探索性R21应用的目标是详细描述基因组背景， 允许产生病毒-人蛋白质，沿着表征，在生理学上， 的方式，由IAV产生的保守的人病毒蛋白的作用。的组合 储备遗传方法将用于产生病毒突变体，并充分表征其 在细胞和生物体水平上的毒性。通过研究未知病原体的作用- 衍生的蛋白质，这一建议有可能建立他们的重要性，阐明他们的作用， 并为未来的病毒学-免疫学-和 基因组研究旨在确定多种病毒中的宿主病毒蛋白， 产生（3个病毒家族，包括人、其他动物和植物病毒）。

SUMMARY The capacity of a pathogen to overcome host barriers and establish infection is based on the expression of pathogen-derived proteins. To understand how a pathogen antagonizes the host and establishes infection, we need to have a clear understanding of what proteins a pathogen encodes, how they function, and in what manner they contribute to virulence. The current dogma about many life-threatening pathogens is that they encode just a handful of proteins because of their limited genome. RNA viruses, like Influenza A virus (IAV), are a prime example of this paradigm. Based on this, our understanding of virus life cycles, pathogenesis, and therapeutic or prophylactic methods of disease containment are limited to a small set of known proteins encoded by the viral genome. We hypothesized that, as a result of host-virus genetic interaction, RNA viruses could generate chimeric host-virus genes that are translated into proteins during infection. In fact, IAV, and many other highly pathogenic viruses, use short host RNAs to prime viral transcription to generate viral mRNA. Thus, we further hypothesized that start codons within host primer sequences could drive the expression of chimeric human-viral coding sequences, a process that would depend on the translatability of the viral UTR sequences. Our recent publication indicates the existence of this mechanism, which creates human-virus protein chimeras either as extensions of canonical viral proteins or novel polypeptides by genetic overprinting. This idea is supported by evolutionary analysis and functional data in a few preliminary case studies. The goal of this exploratory R21 application is to characterize in detail the genomic context that allows the generation of viral-human proteins along with characterizing, in a physiological manner, the role of a conserved human-virus protein generated by IAV. A combination of reserve genetic approaches will be used to generate viral mutants and to fully characterize their virulence at the cellular and organismal level. By investigating the role of unknown pathogen- derived proteins, this proposal has the potential to establish their importance, elucidate their role during infection, and provide a proof-of-principle study for future virology- immunology- and genomic studies aimed at defining host-virus proteins in the multiple virus in which they can be generated (3 viral families comprising human, other animal and plant viruses).