Interaction studies of human DEAD-box helicases with viral non-coding RNA

Abstract

Mosquito-borne illnesses are responsible for millions of deaths every year. Some of the most common diseases spread include Japanese Encephalitis, Zika, and Rift Valley Fever Virus. This thesis seeks to describe the interactions between the non-coding regions of the RNA genomes of the viruses above and DEAD-box RNA helicases DDX3X and DDX17. Microscale thermophoresis indicated that DDX3X binds the JEV 5’ RNA with a lower dissociation constant than the ZIKV 5’ but could unwind both RNAs. DDX17 binds both the intergenic non-coding and 5’ terminal RNAs from the S segment of the genome, also unwinding both. Small-angle X-ray scattering generated low-resolution 3D structures of DDX17 and the non-coding RNAs. Finally, using a baculovirus expression system has shown the potential to express full-length DDX3X but requires optimization before it is ready for downstream experimentation.