Identification of essential host factors in the Bunyamwera virus life cycle through an unbiased genome-wide screening system

Using the Bunyamwera virus (BUNV) as a paradigm of bunyavirus infection, this project describes the development and optimisation of an unbiased, genome-wide, forward mutagenesis approach capable of revealing host factors critical to viral infection. The Sleeping Beauty transposon system has been used in combination with the haploid cell line, eHAP1, to generate BUNV-resistant clones. To mediate survival, these clones have gained a transposition event that either disrupts a gene essential for viral entry, replication, or release, or alternativity upregulates the expression of a host restriction factor. A number of genes with exciting potential involvement in viral infectivity have been identified. Many of the genes identified here are key components in a range of cellular pathways that are critical to BUNV infection, including host proteins involved in endosomal and Golgi trafficking, as well as cell surface proteins that may be essential to viral entry. Although further investigation is required, the genes identified here could potentially serve as novel targets for host-directed therapy against BUNV and perhaps more clinically relevant members of the Bunyavirales order via a conserved dependence on a specific host factor. Ultimately, this work validates the use of transposon mutagenesis as a universal tool for the unbiased interrogation of viral biology.