Monitoring ribosomal frameshifting as a platform to screen anti-riboswitch drug candidates

Riboswitches are regions within mRNAs that can regulate downstream expression of genes through metabolite-induced alteration of their secondary structures. Due to the significant association of bacterial essential or virulence genes, bacterial riboswitches have become promising targets for development of putative antibacterial drugs. However, most of the screening systems to date are based on in vitro or bacterial systems, lacking the possibility to preobserve the adverse effects to the host's translation machinery. This chapter describes a novel screening method based on monitoring the riboswitch-induced - 1 ribosomal frameshifting (- 1 FS) efficiency in a mammalian cell-free lysate system using preQ₁ class-I (preQ₁-I) riboswitches as model target.