A translational riboswitch coordinates nascent transcription–translation coupling
Surajit Chatterjee, Adrien Chauvier, Shiba S. Dandpat, Irina Artsimovitch, Nils G. Walter
Abstract
Significance Transcription–translation coupling is critical for fast and efficient gene expression in many bacteria, yet how coupling between RNA polymerase (RNAP) and ribosome is established and maintained is poorly understood. Combining biochemical and single-molecule fluorescence approaches, we here uncover the roles of nascent mRNA structure and transcription factors in coupling. We find that the inherently paused RNAP facilitates 30S ribosomal subunit recruitment, whereas ligand-induced translational riboswitch folding in the 5′ untranslated region (5′ UTR) impedes it. Transcription factors NusG and RfaH distinctly enhance 30S recruitment and retention, respectively, and actively translating 70S ribosome accelerates the leading RNAP. Taken together, our data yield a unifying dynamic model of transcription–translation coupling, promising to inspire new approaches for the design of antibiotics.