Ribosomal skipping

Ribosomal “skipping” is an alternate mechanism of translation in which a specific viral peptide prevents the ribosome from covalently linking a new inserted aa, and let it continue translation. This result in apparent co-translational cleavage of the polyprotein.
This process is induced by a “2A-like”, or CHYSEL (cis-acting hydrolase element) sequence. This sequence comprises a non-conserved sequence of amino-acids with a strong alpha-helical propensity followed by the consensus sequence -D(V/I)ExNPG P, where x= any amino acid. The apparent cleavage occurs between G and P.
Ribosomal “skipping” has been observed only in +ssRNA and dsRNA viruses, whose hosts are animals, plant or insect. The conserved motif has been identified also in trypanosoma and in some fungus proteins.

Ribosomal “skipping” is functioning both in vitro and in vivo when translated by eukaroytic ribosomes, but is inactive when translated by prokaryotic ribosomes.

Family Genus Virus Sequence ( |= apparent cleavage ) Frequency UniProt
Picornaviridae Aphtovirus Foot-and-mouth disease virus PSDARHKQRIVAPAKQLLNFDLLKLAGDVESNPG|P 99% Q9DLK1
Avisivirus Avisivirua A ARRTLEWARREVGAIDETDHKDILLGGDIEENPG|P 99% M4PJD6
Avihepatovirus Duck hepatitis A virus RLKTLAFELNLEIESDQIRNKKDLTTEGVEPNPG|P 99% Q0ZQM1
Cardiovirus Encephalomyocarditis virus VREENVFGLYRIFNAHYAGYFADLLIHDIETNPG|P 99% Q66765
Cosavirus Cosavirus A IMADSVLPRPLTRAERDVARDLLLIAGDIESNPG|P 99% B8XTP8
Erbovirus Equine rhinitis B virus 1 SEPIPEATLSTILSEGATNFSLLKLAGDVELNPG|P 99% Q66776
Erbovirus Seneca Valley virus RYKNARAWCPSMLPFRSYKQKMLMQSGDIETNPG|P 99% Q155Z9
Hunnivirus Hunnivirus A CPRPGMAIDPPAQSSGATNFSLLRLAGDVELNPG|P 99% F4YYF3
Kunsagivirus???? Kunsagivirus A SPRSLLHFLIGRPRPRVPPSPSLLLSGDVEPNPG|P NA S4VD62
Mischivirus Mischivirus A DSYPASGEEEEDDFHDMEDHSDILLGGDVEENPG|P 99% I3VR62
Mosavirus Mosavirus A2 TNSRAKLMVDEDYVIQRSAHRSVLLDGDVESNPG|P 99% X2L6K2
Pasivirus Pasivirus A1 DIPSFQRDFINWLGSKEELQNMILQCGDVEQNPG|P 99% I6YQK4
Teschovirus Porcine teschovirus 1 EGLSSAMTVMAFQGPGATNFSLLKQAGDVEENPG|P 99% Q9WJ28
Iflaviridae Iflavirus Infectious flacherie virus NYPLVPSIGNVARTLTRAEIEDELIRAGIESNPG|P 99% O70710
Tetraviridae Betatetravirus Thosea asigna virus RSRRLRGPRPQNLGVRAEGRGSLLTCGDVEENPG|P 94-99% Q9YK87
Dicistroviridae Cripavirus Cricket paralysis virus FQQWKLVSSNDECRAFLRKRTQLLMSGDVESNPG|P 88% Q9IJX4
Reoviridae Rotavirus Human rotavirus C LKKHNGAGYPLIVANSKFQIDKILISGDIELNPG|P 82% Q9PY95
Cypovirus Lymantria dispar cypovirus 1 TDFLSMTAFDFQQAVFRSNYDLLKLCGDVESNPG|P 99% Q91ID7



References
Luke GA, de Felipe P, Lukashev A, Kallioinen SE, Bruno EA, Ryan MD.
Occurrence, function and evolutionary origins of ‘2A-like’ sequences in virus genomes.
J Gen Virol. 2008 Apr;89(Pt 4):1036-42. PubMed

Doronina VA, de Felipe P, Wu C, Sharma P, Sachs MS, Ryan MD, Brown JD.
Dissection of a co-translational nascent chain separation event.
Biochem Soc Trans. 2008 Aug;36(Pt 4):712-6. PubMed

Martin D. Ryan, Michelle Donnelly, Arwel Lewis, Amit P. Mehrotra, John Wilkie, David Gani.
A Model for Nonstoichiometric, Cotranslational Protein Scission in Eukaryotic Ribosomes.
Bioorganic Chemistry, Volume 27, Issue 1, February 1999, 55-79 link