When a ribosome encounters a premature termination codon.
In mammalian cells, aberrant transcripts harboring a premature termination codon (PTC) can be generated by abnormal or inefficient biogenesis of mRNAs or by somatic mutation. Truncated polypeptides synthesized from these aberrant transcripts could be toxic to normal cellular functions. However, mammalian cells have evolved sophisticated mechanisms for monitoring the quality of mRNAs. The faulty transcripts harboring PTC are subject to nonsense-mediated mRNA decay (NMD), nonsense-mediated translational repression (NMTR), nonsense-associated alternative splicing (NAS), or nonsense-mediated transcriptional gene silencing (NMTGS). In this review, we briefly outline the molecular characteristics of each pathway and suggest mRNA quality control mechanisms as a means to regulate normal gene expression.
Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Korea.
Jungwook
J
Hwang
Yoon Ki
YK
Kim
D017398:Alternative Splicing; D000818:Animals; D018389:Codon, Nonsense / Q000378:metabolism*; D020868:Gene Silencing; D006801:Humans; D059365:Nonsense Mediated mRNA Decay; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*
D018389:Codon, Nonsense; D012333:RNA, Messenger