Codon codes: Codon usage bias influences many levels of gene expression

Abstract

Synonymous mutations, which do not change the primary sequences of encoded proteins, are often recognized as silent mutations. In particular, the selection of synonymous codons at an evolutionary scale is constrained and has resulted in uneven occurrences, a phenomenon called codon usage bias. In recent decades, the roles of codon usage bias in fine-tuning transcription, post-transcriptional processing, mRNA stability, translation initiation, elongation, and peptide folding have been revealed. Upon disrupting these biological processes, synonymous mutations have been reported to cause various diseases such as cancer. Herein, we briefly review the current understanding concerning the molecular mechanisms of transcription and translation processes regulated by codon usage bias as well as the implications for basic and translational research inmedicine.