Ribosomal pause

The ribosome assembles polymeric protein molecules whose sequence is controlled by the sequence of messenger RNA molecules. This is required by all living cells and associated viruses.

Ribosomal pause refers to the queueing or stacking of ribosomes during translation of the nucleotide sequence of mRNA transcripts. These transcripts are decoded and converted into amino acid sequence during protein synthesis by ribosomes. Within the ribosome, transfer RNA molecules recognise specific trinucleotide codons on the mRNA, and add their cognate amino acids to nascent protein chains.[1][2]

It’s been known since the 1980s that different mRNAs are translated at different rates. The main reason for these differences was thought to be the concentration of rarer varieties of tRNA limiting the rate at which some transcripts could be decoded.[3]

Effects on gene expression

During protein synthesis, rapidly changing conditions in the cell can cause ribosomal pausing. In bacteria and viruses, this can affect growth rate and trigger translational abandonment. This releases the ribsome from the mRNA and the incomplete polypeptide is targeted for destruction.[4]

In eukaryotes, ribosomal pausing can initiate an analogous process which triggers endonucleolytic attack of the mRNA, a process termed mRNA no-go decay. Ribosomal pausing also aids co-translational folding of the nascent polypeptide on the ribosome, and delays protein translation while its encoding mRNA. This can trigger ribosomal frameshifting.[5]

See also

References

  1. ↑ Jha SS, Komar AA. Isolation of ribosome bound nascent polypeptides in vitro to identify translational pause sites along mRNA. J Vis Exp. 2012 Jul 6;(65). pii: 4026. doi: 10.3791/4026.
  2. ↑ John D. Lopinski, Jonathan D. Dinman, Jeremy A. Bruenn. Kinetics of Ribosomal Pausing during Programmed −1 Translational Frameshifting. Mol. Cell. Biol. February 2000 vol. 20 no. 4 1095-1103.
  3. ↑ Harry Kontos†, Sawsan Napthine, and Ian Brierley, Harry Kontos, Sawsan Napthine, and Ian Brierley. Ribosomal Pausing at a Frameshifter RNA Pseudoknot Is Sensitive to Reading Phase but Shows Little Correlation with Frameshift Efficiency. Mol. Cell. Biol. December 2001 vol. 21 no. 24 8657-8670
  4. ↑ Buchan JR, Stansfield I. Halting a cellular production line: responses to ribosomal pausing during translation. Biol Cell. 2007 Sep;99(9):475-87.
  5. ↑ Buchan JR, Stansfield I. Halting a cellular production line: responses to ribosomal pausing during translation. Biol Cell. 2007 Sep;99(9):475-87.

External links