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Theses and Dissertations

2009

Stalling

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Full-Text Articles in Physical Sciences and Mathematics

The Role Of Smpb In The Early Stages Of Trans-Translation, Deanna June Cazier Jul 2009

The Role Of Smpb In The Early Stages Of Trans-Translation, Deanna June Cazier

Theses and Dissertations

Ribosomes stall on defective messenger RNA transcripts in eubacteria. Without a mechanism to release stalled ribosomes, these cells would die. Transfer-messenger RNA (tmRNA) and small protein B (SmpB) reactivate stalled ribosomes in a process known as trans-translation. Together, tmRNA and SmpB mimic alanyl-tRNA, entering the A site of stalled ribosomes and accepting transfer of the stalled polypeptide. A portion of tmRNA is then positioned as a template for the ribosome to resume translating. The tmRNA open reading frame encodes a proteolysis tag to mark the aberrant polypeptide for degradation and a stop codon to release the ribosome. How are tmRNA …


Genetic Analysis Of Ribosome Stalling And Rescue, Douglas Ray Tanner May 2009

Genetic Analysis Of Ribosome Stalling And Rescue, Douglas Ray Tanner

Theses and Dissertations

In eubacteria, ribosome stalling on broken messenger RNA transcripts can lead to cell death. The trans-translation quality control mechanism rescues many of these stalled ribosomes. In this process, tmRNA enters stalled ribosomes by mimicking a transfer RNA, accepting the stalled nascent peptide. The ribosome then releases the broken mRNA and resumes translation on a coding region within tmRNA itself. Translation of tmRNA marks the nascent peptide for destruction by the addition of a short proteolysis tag and the ribosome is released at a stop codon within the tmRNA open reading frame. An intriguing aspect of trans-translation is that …