Grant: Discovery Grants Program - Individual

The flow of genetic information begins with DNA being transcribed into many different messenger RNAs (mRNAs). The mRNAs are then translated into specific proteins, which together comprise the functional building blocks required for life. Protein expression was originally thought to be primarily controlled by how much DNA is transcribed into specific mRNAs. However we now know that highly expressed mRNAs are sometimes weakly translated into proteins while poorly expressed mRNAs can be synthesized abundantly. Therefore, the factors that control mRNA translation play a vital role in regulating the amount of proteins synthesized from distinct mRNAs. Translation control strongly contributes to critical cellular functions, such as proliferation, growth, and metabolism, as well as mounting efficient responses to stresses such as nutrient deprivation and, most particularly for this application, viral infection. Previous analyses of cellular response to viral infection have primarily assessed total mRNA content (transcription). This led to the identification of multiple anti-viral host factors regulated at the transcription level during infection. In view of the active role of the protein synthesis machinery (mRNA translation) under stress, we have examined the specific mRNAs actively translated into proteins when cells are infected with viral models of different families of RNA and DNA viruses (Reoviridae, Rhabdoviridae, Herpesviridae and Poxviridae). Our translatome profiling data have revealed interesting transcript targets regulated at the translation level during infection. Furthermore, through these analyses, we have defined viral-specific elements that can mediate increased translation of transgenes encoded within viral vectors. The current research program is designed to characterize the factors that mediate translation mechanisms and describe their functions in host-viral vector interactions.  This proposal exploits our analyses on the translatome to explore translation regulation of virally infected cells, and presents innovative strategies to optimize protein production from viral-encoded transgenes. We hypothesize that incorporating viral 5'leaders and specific codons that are matched to the exact viral vector platform will enhance expression of transgenic proteins. We will dissect the intracellular signals involved, and using a combination of biochemical, molecular biology and genetic experimental approaches, assess translation control mechanisms and cis-acting elements. We have a unique opportunity and pipeline to make a significant impact by identifying and characterizing novel viral translation regulatory elements. Our data will shed light on the importance of translational control mechanisms in response to viral infection and establish regulators of translation that be utilized in the development of next-generation viral-based technologies.