RT Journal Article
SR Electronic
T1 mRNA stem-loops can pause the ribosome by hindering A-site tRNA binding
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.02.05.936120
DO 10.1101/2020.02.05.936120
A1 Bao, Chen
A1 Loerch, Sarah
A1 Ling, Clarence
A1 Korostelev, Andrei A.
A1 Grigorieff, Nikolaus
A1 Ermolenko, Dmitri N.
YR 2020
UL http://biorxiv.org/content/early/2020/02/06/2020.02.05.936120.abstract
AB 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.