Coronavirus protein processing and RNA synthesis is inhibited by the cysteine proteinase inhibitor E64d.
Mouse hepatitis virus strain A59 (MHV-A59) encodes within the 22-kb gene 1 a large polyprotein containing three proteinase domains with proven or predicted cysteine catalytic residues. E64d, a specific, irreversible inhibitor of cysteine (thiol) proteinases, inhibits the processing of the gene 1 polyprotein. Specifically, E64d blocks the carboxy-terminal cleavage of p65. E64d also inhibits replication of MHV-A59 in murine DBT cells in a dose-dependent manner, resulting in reduced virus titers and viral syncytia formation. This inhibition of replication is associated with a rapid shutoff of new viral RNA synthesis, in a manner similar to that seen in the presence of cycloheximide. The E64d-associated inhibition of RNA synthesis likely results from E64d-specific inhibition of processing of the gene 1 polyprotein, resulting in inactive proteinase or replicase proteins. These results indicate that processing of the MHV-A59 gene 1-encoded polyprotein is required throughout infection to sustain RNA synthesis and virus replication.
Kim
J C
JC
Department of Pediatrics, Vanderbilt Medical School, Nashville, Tennessee 37232-2581, USA.
Spence
R A
RA
Currier
P F
PF
Lu
X
X
Denison
M R
MR
D000818:Animals; D002478:Cells, Cultured; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D007930:Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D051379:Mice; D006517:Murine hepatitis virus / Q000187:drug effects* / Q000502:physiology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D012367:RNA, Viral / Q000096:biosynthesis / Q000187:drug effects; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication / Q000187:drug effects
D015853:Cysteine Proteinase Inhibitors; D012367:RNA, Viral; D014764:Viral Proteins; C087637:gene 1 protein, Coronavirus; D007930:Leucine; C108192:aloxistatin