Dataset Information

Mechanism of tRNA-mediated +1 ribosomal frameshifting.

ABSTRACT: Accurate translation of the genetic code is critical to ensure expression of proteins with correct amino acid sequences. Certain tRNAs can cause a shift out of frame (i.e., frameshifting) due to imbalances in tRNA concentrations, lack of tRNA modifications or insertions or deletions in tRNAs (called frameshift suppressors). Here, we determined the structural basis for how frameshift-suppressor tRNASufA6 (a derivative of tRNAPro) reprograms the mRNA frame to translate a 4-nt codon when bound to the bacterial ribosome. After decoding at the aminoacyl (A) site, the crystal structure of the anticodon stem-loop of tRNASufA6 bound in the peptidyl (P) site reveals ASL conformational changes that allow for recoding into the +1 mRNA frame. Furthermore, a crystal structure of full-length tRNASufA6 programmed in the P site shows extensive conformational rearrangements of the 30S head and body domains similar to what is observed in a translocation intermediate state containing elongation factor G (EF-G). The 30S movement positions tRNASufA6 toward the 30S exit (E) site disrupting key 16S rRNA-mRNA interactions that typically define the mRNA frame. In summary, this tRNA-induced 30S domain change in the absence of EF-G causes the ribosome to lose its grip on the mRNA and uncouples the canonical forward movement of the tRNAs during elongation.

SUBMITTER: Hong S

PROVIDER: S-EPMC6217423 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Mechanism of tRNA-mediated +1 ribosomal frameshifting.

Hong Samuel S Sunita S S Maehigashi Tatsuya T Hoffer Eric D ED Dunkle Jack A JA Dunham Christine M CM

Proceedings of the National Academy of Sciences of the United States of America 20180927 44

Accurate translation of the genetic code is critical to ensure expression of proteins with correct amino acid sequences. Certain tRNAs can cause a shift out of frame (i.e., frameshifting) due to imbalances in tRNA concentrations, lack of tRNA modifications or insertions or deletions in tRNAs (called frameshift suppressors). Here, we determined the structural basis for how frameshift-suppressor tRNA<sup>SufA6</sup> (a derivative of tRNA<sup>Pro</sup>) reprograms the mRNA frame to translate a 4-nt ...[more]

PMID: 30262649

Similar Datasets

Project description:The -2/-1 programmed ribosomal frameshifting (-2/-1 PRF) mechanism in porcine reproductive and respiratory syndrome virus (PRRSV) leads to the translation of two additional viral proteins, nonstructural protein 2TF (nsp2TF) and nsp2N. This -2/-1 PRF mechanism is transactivated by a viral protein, nsp1β, and cellular poly(rC) binding proteins (PCBPs). Critical elements for -2/-1 PRF, including a slippery sequence and a downstream C-rich motif, were also identified in 11 simarteriviruses. However, the slippery sequences (XXXUCUCU instead of XXXUUUUU) in seven simarteriviruses can only facilitate -2 PRF to generate nsp2TF. The nsp1β of simian hemorrhagic fever virus (SHFV) was identified as a key factor that transactivates both -2 and -1 PRF, and the universally conserved Tyr111 and Arg114 in nsp1β are essential for this activity. In vitro translation experiments demonstrated the involvement of PCBPs in simarterivirus -2/-1 PRF. Using SHFV reverse genetics, we confirmed critical roles of nsp1β, slippery sequence, and C-rich motif in -2/-1 PRF in SHFV-infected cells. Attenuated virus growth ability was observed in SHFV mutants with impaired expression of nsp2TF and nsp2N. Comparative genomic sequence analysis showed that key elements of -2/-1 PRF are highly conserved in all known arteriviruses except equine arteritis virus (EAV) and wobbly possum disease virus (WPDV). Furthermore, -2/-1 PRF with SHFV PRF signal RNA can be stimulated by heterotypic nsp1βs of all non-EAV arteriviruses tested. Taken together, these data suggest that -2/-1 PRF is an evolutionarily conserved mechanism employed in non-EAV/-WPDV arteriviruses for the expression of additional viral proteins that are important for viral replication.IMPORTANCE Simarteriviruses are a group of arteriviruses infecting nonhuman primates, and a number of new species have been established in recent years. Although these arteriviruses are widely distributed among African nonhuman primates of different species, and some of them cause lethal hemorrhagic fever disease, this group of viruses has been undercharacterized. Since wild nonhuman primates are historically important sources or reservoirs of human pathogens, there is concern that simarteriviruses may be preemergent zoonotic pathogens. Thus, molecular characterization of simarteriviruses is becoming a priority in arterivirology. In this study, we demonstrated that an evolutionarily conserved ribosomal frameshifting mechanism is used by simarteriviruses and other distantly related arteriviruses for the expression of additional viral proteins. This mechanism is unprecedented in eukaryotic systems. Given the crucial role of ribosome function in all living systems, the potential impact of the in-depth characterization of this novel mechanism reaches beyond the field of virology.

Dataset Information

Mechanism of tRNA-mediated +1 ribosomal frameshifting.

Publications

Mechanism of tRNA-mediated +1 ribosomal frameshifting.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets