Ribosome–messenger RNA complex at premature termination codon (UAG)

The ribosome–messenger RNA (mRNA) complex at a premature termination codon (PTC), specifically at a UAG (TAG) stop codon, refers to the assembly of the ribosome as it encounters a stop codon that arises within the coding region of an mRNA due to a nonsense mutation. When the ribosome reaches a PTC, translation termination is triggered prematurely, leading to the synthesis of truncated, and often nonfunctional or deleterious, proteins. In eukaryotic cells, such PTC-containing transcripts are recognized and targeted by the nonsense-mediated mRNA decay (NMD) pathway, which serves as a quality control mechanism to degrade faulty mRNAs and prevent accumulation of potentially toxic truncated proteins. Pharmacological agents such as ataluren and certain aminoglycosides can induce 'readthrough' of these premature stop codons, allowing translation to continue and partially restore protein expression. Dysfunction in this process is implicated in various genetic diseases and cancers due to the effects of faulty or absent proteins.

Other names

Ribosome–mRNA complex at premature stop codonRibosome–PTC complexRibosome–mRNA–PTC complex

Induction of readthrough at premature termination codon; Promotion or inhibition of nonsense-mediated mRNA decay (NMD)