Occurrence, function and evolutionary origins of ‘2A-like’ sequences in virus genomes

• DOI: 10.1099/vir.0.83428-0
• Publication Date: 2008-03-14T06:38:13Z
• Authors: Garry A. Luke; Pablo de Felipe; Alexander Lukashev; Susanna E. Kallio...; Elizabeth A. Bruno; Martin D. Ryan
• Keywords: Polyproteins; Cleavage (geology); Conserved sequence

2A is an oligopeptide sequence mediating a ribosome 'skipping' effect, producing apparent 'cleavage' of polyproteins. First identified and characterized in picornaviruses, '2A-like' sequences are found other mammalian viruses wide range insect viruses. Databases were analysed using motif conserved amongst 2A/2A-like sequences. The newly 2A-like (30 aa) inserted into reporter polyprotein to determine their cleavage activity. Our analyses showed that these fall two categories. majority mediated very high (complete) separate proteins few with lower efficiency, generating appreciable levels the uncleaved form. Phylogenetic RNA-dependent RNA polymerases (RdRps) indicated multiple, independent, acquisitions at different stages during virus evolution. Within family, (probably) homologous, but diverge due evolutionary pressures. Amongst families, however, appear be homoplasic.