%0 Journal Article %A Luke, Garry A. %A de Felipe, Pablo %A Lukashev, Alexander %A Kallioinen, Susanna E. %A Bruno, Elizabeth A. %A Ryan, Martin D. %T Occurrence, function and evolutionary origins of ‘2A-like’ sequences in virus genomes %D 2008 %J Journal of General Virology, %V 89 %N 4 %P 1036-1042 %@ 1465-2099 %R https://doi.org/10.1099/vir.0.83428-0 %I Microbiology Society, %X 2A is an oligopeptide sequence mediating a ribosome ‘skipping’ effect, producing an apparent ‘cleavage’ of polyproteins. First identified and characterized in picornaviruses, ‘2A-like’ sequences are found in other mammalian viruses and a wide range of insect viruses. Databases were analysed using a motif conserved amongst 2A/2A-like sequences. The newly identified 2A-like sequences (30 aa) were inserted into a reporter polyprotein to determine their cleavage activity. Our analyses showed that these sequences fall into two categories. The majority mediated very high (complete) cleavage to separate proteins and a few sequences mediated cleavage with lower efficiency, generating appreciable levels of the uncleaved form. Phylogenetic analyses of 2A-like sequences and RNA-dependent RNA polymerases (RdRps) indicated multiple, independent, acquisitions of these sequences at different stages during virus evolution. Within a virus family, 2A sequences are (probably) homologous, but diverge due to other evolutionary pressures. Amongst different families, however, 2A/2A-like sequences appear to be homoplasic. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.83428-0