RNA Therapeutics Institute; Department of Biochemistry and Molecular Pharmacology
Biochemical Phenomena, Metabolism, and Nutrition | Biochemistry | Enzymes and Coenzymes | Genetic Phenomena | Nucleic Acids, Nucleotides, and Nucleosides
Although the elongating ribosome is an efficient helicase, certain mRNA stem-loop structures are known to impede ribosome movement along mRNA and stimulate programmed ribosome frameshifting via mechanisms that are not well understood. Using biochemical and single-molecule Förster resonance energy transfer (smFRET) experiments, we studied how frameshift-inducing stem-loops from E. coli dnaX mRNA and the gag-pol transcript of Human Immunodeficiency Virus (HIV) perturb translation elongation. We find that upon encountering the ribosome, the stem-loops strongly inhibit A-site tRNA binding and ribosome intersubunit rotation that accompanies translation elongation. Electron cryo-microscopy (cryo-EM) reveals that the HIV stem-loop docks into the A site of the ribosome. Our results suggest that mRNA stem-loops can transiently escape ribosome helicase by binding to the A site. Thus, the stem-loops can modulate gene expression by sterically hindering tRNA binding and inhibiting translation elongation.
Biochemistry, mRNA, ribosomes, tRNA binding, frameshift-inducing stem-loops, helicases, Förster resonance energy transfer, E. coli dnaX, Human Immunodeficiency Virus
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DOI of Published Version
bioRxiv 2020.02.05.936120; doi: https://doi.org/10.1101/2020.02.05.936120. Link to preprint on bioRxiv service.
Bao C, Loerch S, Ling C, Korostelev AA, Grigorieff N, Ermolenko DN. (2020). mRNA stem-loops can pause the ribosome by hindering A-site tRNA binding. University of Massachusetts Medical School Faculty Publications. https://doi.org/10.1101/2020.02.05.936120. Retrieved from https://escholarship.umassmed.edu/faculty_pubs/1670
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