Foot-and-mouth disease virus 3C protease induces cleavage of translation initiation factors eIF4A and eIF4G within infected cells.
Infection of cells by foot-and-mouth disease virus (FMDV) results in the rapid inhibition of host cell protein synthesis. This process is accompanied by the early cleavage of the translation initiation factor eIF4G, a component of the cap-binding complex eIF4F. This cleavage is mediated by the leader (L) protease. Subsequently, as the virus proteins accumulate, secondary cleavages of eIF4G occur. Furthermore, eIF4A (46 kDa), a second component of eIF4F, is also cleaved in these later stages of the infection cycle. The 33-kDa cleavage product of eIF4A has lost a fragment from its N terminus. Transient-expression assays demonstrated that eIF4A was not cleaved in the presence of FMDV L or with the poliovirus 2A protease (which also mediates eIF4G cleavage) but was cleaved when the FMDV 3C protease was expressed. The FMDV 3C protease was also shown in such assays to induce cleavage of eIF4G, resulting in the production of cleavage products different from those generated by the L protease. Consistent with these results, within cells infected with a mutant FMDV lacking the L protease or within cells containing an FMDV replicon lacking L-P1 coding sequences it was again shown that eIF4A and eIF4G were cleaved.
Belsham
G J
GJ
BBSRC Institute for Animal Health, Pirbright, Woking, Surrey GU24 0NF, United Kingdom. graham.belsham@bbsrc.ac.uk
McInerney
G M
GM
Ross-Smith
N
N
D000086042:3C Viral Proteases; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D039601:Eukaryotic Initiation Factor-4A; D039603:Eukaryotic Initiation Factor-4G; D006868:Hydrolysis; D010448:Peptide Initiation Factors / Q000378:metabolism*; D014176:Protein Biosynthesis; D014764:Viral Proteins
D039603:Eukaryotic Initiation Factor-4G; D010448:Peptide Initiation Factors; D014764:Viral Proteins; D039601:Eukaryotic Initiation Factor-4A; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases