Regulation of Filovirus mRNA translation

Abstract Project Summary Filoviruses, including Ebola virus, belong to the group of non-segmented negative-strand RNA viruses (nsNSVs) and are significant human pathogens. During transcription, filoviruses produce capped and polyadenylated mRNAs that resemble cellular mRNAs. The pathogenicity of any virus is dependent upon its ability to effectively and efficiently synthesize proteins encoded by their genetic information. However, unlike mRNAs from other nsNSVs, filovirus mRNAs contain structural elements that impose additional constraints on canonical protein synthesis. Whereas most other nsNSV mRNAs have short, unstructured 5' untranslated regions (5'UTRs), filovirus mRNAs possess extended, highly structured 5'UTRs. Our preliminary biochemical analyses suggest these structures hinder canonical cap-dependent translation, yet filovirus mRNAs are efficiently translated during infection. We hypothesize that viral infection modifies the intracellular environment to facilitate the translation of these suboptimal mRNAs. Our research aims to identify the requirements for optimal filovirus translation and the cellular proteins that promote this process. To this end, we will develop novel recombinant reporter viruses to precisely measure viral protein synthesis rates. These measurements are crucial for understanding mRNA translation and are commonly used for cellular mRNAs. However, biosafety restrictions have limited their use in studying highly pathogenic viruses, where such insights are most needed. Our innovative approach also includes the use of auxin-inducible degrons to rapidly deplete cellular proteins potentially involved in filoviral mRNA translation. We anticipate that the proposed work will provide new insights into the mechanisms and requirements for filovirus mRNA translation.