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How translational accuracy influences reading frame maintenance
1Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA.
The EMBO Journal
|March 17, 1999
Summary
Most protein synthesis errors have minor effects, but frameshifting errors create incomplete peptides. A new dual-error model suggests these frameshifting errors, including those by suppressor tRNAs, share a common mechanism inherent to the ribosome.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Missense errors typically cause minimal protein dysfunction.
- Processivity errors, such as frameshifting or premature termination, lead to incomplete peptide synthesis.
- A potential link exists between missense and processivity errors.
Purpose of the Study:
- To investigate the connection between missense and processivity errors in protein synthesis.
- To propose a dual-error model for frameshifting, explaining both spontaneous and programmed events.
- To re-evaluate the role of suppressor tRNAs in frameshifting mechanisms.
Main Methods:
- Analysis of translational errors, including missense, frameshifting, and premature termination.
- Examination of programmed translational frameshifting mechanisms.
- Investigation of suppressor tRNA function in translation.
Main Results:
- Processivity errors may arise from a second error following errant aminoacyl-tRNA recruitment.
- A dual-error model explains programmed frameshifting, where mRNA directs a near-cognate tRNA to induce a second frameshift.
- This mechanism also accounts for frameshifting induced by suppressor tRNAs, challenging the quadruplet translocation model.
- Spontaneous and programmed frameshifting likely share a common mechanism, differing mainly in frequency.
Conclusions:
- A unified dual-error model explains various frameshifting phenomena, including those involving suppressor tRNAs.
- The ribosome's inherent translocation of three nucleotides, rather than the tRNA, may be the fundamental step in frameshifting.
- This revised understanding impacts the study of genetic errors and protein synthesis fidelity.