title: APE-type non-LTR retrotransposons of multicellular organisms encode virus-like 2A oligopeptide sequences, which mediate translational recoding during protein synthesis.
abstract: 2A oligopeptide sequences ("2As") mediate a cotranslational recoding event termed "ribosome skipping." Previously we demonstrated the activity of 2As (and "2A-like sequences") within a wide range of animal RNA virus genomes and non-long terminal repeat retrotransposons (non-LTRs) in the genomes of the unicellular organisms Trypanosoma brucei (Ingi) and T. cruzi (L1Tc). Here, we report the presence of 2A-like sequences in the genomes of a wide range of multicellular organisms and, as in the trypanosome genomes, within non-LTR retrotransposons (non-LTRs)-clustering in the Rex1, Crack, L2, L2A, and CR1 clades, in addition to Ingi. These 2A-like sequences were tested for translational recoding activity, and highly active sequences were found within the Rex1, L2, CR1, and Ingi clades. The presence of 2A-like sequences within non-LTRs may not only represent a method of controlling protein biogenesis but also shows some correlation with such apurinic/apyrimidinic DNA endonuclease-type non-LTRs encoding one, rather than two, open reading frames (ORFs). Interestingly, such non-LTRs cluster with closely related elements lacking 2A-like recoding elements but retaining ORF1. Taken together, these observations suggest that acquisition of 2A-like translational recoding sequences may have played a role in the evolution of these elements.
authors.affiliation: Biomedical Sciences Research Complex, Biomolecular Sciences Building, University of St Andrews, Fife, United Kingdom.
authors.forename: Valerie
authors.initials: V
authors.lastname: Odon
authors.forename: Garry A
authors.initials: GA
authors.lastname: Luke
authors.forename: Claire
authors.initials: C
authors.lastname: Roulston
authors.forename: Pablo
authors.initials: P
authors.lastname: de Felipe
authors.forename: Lin
authors.initials: L
authors.lastname: Ruan
authors.forename: Helena
authors.initials: H
authors.lastname: Escuin-Ordinas
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Brown
authors.forename: Martin D
authors.initials: MD
authors.lastname: Ryan
authors.forename: Andriy
authors.initials: A
authors.lastname: Sukhodub
mesh_terms: D000595:Amino Acid Sequence; D018503:Genome, Protozoan; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry / Q000235:genetics*; D016366:Open Reading Frames; D010802:Phylogeny; D014176:Protein Biosynthesis / Q000502:physiology*; D018626:Retroelements / Q000235:genetics*; D016415:Sequence Alignment; D014345:Trypanosoma / Q000145:classification / Q000235:genetics* / Q000378:metabolism*
chemical_list: D009842:Oligopeptides; D018626:Retroelements
keywords: 2A-like sequences; APE-type non-LTR; retrotransposon; translational recoding