Biophysical characterization of Zika virus terminal region interactions

Abstract

Recent viral threats have intensified research into viral mechanisms and the various interactions during their viral life cycle. Viruses such as Zika virus have continued to threaten healthcare systems around the globe, with large outbreaks affecting over 3 million people within the last decade. While viral proteins have received significant attention, the untranslated terminal regions (TRs) flanking the single-stranded RNA genome play crucial roles in the viral life cycle. These TRs facilitate replication through interactions with host/viral proteins and through self-association via cyclization, which regulates transcription and translation. This thesis characterizes the biophysical and cellular properties of this cyclization interaction and the TRs interaction with the host protein FXR1. Using size exclusion multi-angle light scattering and analytical ultracentrifugation, we defined the hydrodynamic profiles of the TRs and FXR1. Microscale thermophoresis quantified the affinity and specificity of the TRs cyclization interaction, as well as the affinity of FXR1 for the TRs. Cellular studies further demonstrated that TR mutations disrupting cyclization drastically reduce viral replication. Collectively, this work identifies a sequence specific interaction governing Zika virus replication and establishes a foundation for characterizing the TR-FXR1 interaction, offering potential targets for future therapeutic development.