Random mutagenesis defines a domain of Theiler's virus leader protein that is essential for antagonism of nucleocytoplasmic trafficking and cytokine gene expression.
The leader protein of cardioviruses, Theiler's murine encephalomyelitis virus (TMEV) and encephalomyocarditis virus (EMCV), is a multifunctional protein known to antagonize type I interferon expression and to interfere with nucleocytoplasmic trafficking of host proteins and mRNA. This protein plays an important role in the capacity of TMEV to establish persistent infection of the central nervous system. Mutant forms of the TMEV leader protein were generated by random mutagenesis and selected after retroviral transduction on the basis of the loss of the highly toxic nature of this protein. Selected mutations define a short C-terminal domain of the leader conserved in TMEV and Saffold virus but lacking in the EMCV leader and thus called the Theilo domain. Mutations in this domain had a dramatic impact on TMEV L protein activity. Like the zinc finger mutation, Theilo domain mutations affected all of the activities of the L protein tested: interferon gene transcription and IRF-3 dimerization antagonism, alteration of nucleocytoplasmic trafficking, nucleoporin 98 hyperphosphorylation, and viral persistence in vivo. This suggests that the Zn finger and the Theilo domain of the protein cooperate for function. Moreover, the fact that all of the activities tested were affected by these mutations suggests that the various leader protein functions are somehow coupled.
Ricour
Céline
C
Université catholique de Louvain, de Duve Institute, Brussels, Belgium.
Borghese
Fabian
F
Sorgeloos
Frédéric
F
Hato
Stanleyson V
SV
van Kuppeveld
Frank J M
FJ
Michiels
Thomas
T
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D018188:Cardiovirus Infections / Q000235:genetics / Q000821:virology; D002460:Cell Line; D016207:Cytokines / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D016296:Mutagenesis; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017945:Theilovirus / Q000235:genetics* / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
D016207:Cytokines; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins