Non-AUG start codons: Expanding and regulating the small and alternative ORFeome

Exp Cell Res. 2020 Jun 1;391(1):111973. doi: 10.1016/j.yexcr.2020.111973. Epub 2020 Mar 21.

Abstract

Recent ribosome profiling and proteomic studies have revealed the presence of thousands of novel coding sequences, referred to as small open reading frames (sORFs), in prokaryotic and eukaryotic genomes. These genes have defied discovery via traditional genomic tools not only because they tend to be shorter than standard gene annotation length cutoffs, but also because they are, as a class, enriched in sequence properties previously assumed to be unusual, including non-AUG start codons. In this review, we summarize what is currently known about the incidence, efficiency, and mechanism of non-AUG start codon usage in prokaryotes and eukaryotes, and provide examples of regulatory and functional sORFs that initiate at non-AUG codons. While only a handful of non-AUG-initiated novel genes have been characterized in detail to date, their participation in important biological processes suggests that an improved understanding of this class of genes is needed.

Keywords: Genomics; Non-AUG start Codon; Proteomics; Small ORF; sORF.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Codon, Initiator / chemistry*
  • Codon, Initiator / metabolism
  • Computational Biology / methods
  • Eukaryota / genetics
  • Eukaryota / metabolism
  • Genome*
  • High-Throughput Nucleotide Sequencing
  • Molecular Sequence Annotation / methods
  • Open Reading Frames*
  • Peptide Chain Initiation, Translational*
  • Prokaryotic Cells / metabolism
  • Protein Sorting Signals / genetics
  • Proteome / classification
  • Proteome / genetics*
  • Proteome / metabolism
  • Ribosomes / classification
  • Ribosomes / genetics*
  • Ribosomes / metabolism

Substances

  • Codon, Initiator
  • Protein Sorting Signals
  • Proteome