Identification of amino acid residues critical for the anti-interferon activity of the nucleoprotein of the prototypic arenavirus lymphocytic choriomeningitis virus.
Lymphocytic choriomeningitis virus (LCVM) nucleoprotein (NP) counteracts the host type I interferon (IFN) response by inhibiting activation of the IFN regulatory factor 3 (IRF3). In this study, we have mapped the regions and specific amino acid residues within NP involved in its anti-IFN activity. We identified a region spanning residues 382 to 386 as playing a critical role in the IFN-counteracting activity of NP. Alanine substitutions at several positions within this region resulted in NP mutants that lacked the IFN-counteracting activity but retained their functions in virus RNA synthesis and assembly of infectious particles. We used reverse genetics to rescue a recombinant LCMV strain carrying mutation D382A in its NP [rLCMV/NP*(D382A)]. Compared to wild-type (WT) LCMV, rLCMV/NP*(D382A) exhibited a higher level of attenuation in IFN-competent than IFN-deficient cells. In addition, A549 cells infected with rLCMV/NP*(D382A), but not with WT LCMV, produced IFN and failed to rescue replication of the IFN-sensitive Newcastle disease virus.
Martínez-Sobrido
Luis
L
Department of Immunology, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, New York 10029, USA.
Emonet
Sébastien
S
Giannakas
Panagiotis
P
Cubitt
Beatrice
B
García-Sastre
Adolfo
A
de la Torre
Juan C
JC
D019943:Amino Acid Substitution; D000596:Amino Acids / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D006801:Humans; D050838:Interferon Regulatory Factor-3 / Q000235:genetics / Q000378:metabolism; D007370:Interferon Type I / Q000276:immunology*; D008217:Lymphocytic choriomeningitis virus / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D009154:Mutation; D009522:Newcastle disease virus / Q000235:genetics / Q000276:immunology; D009698:Nucleoproteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010641:Phenotype; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
D000596:Amino Acids; D050838:Interferon Regulatory Factor-3; D007370:Interferon Type I; D009698:Nucleoproteins; D014764:Viral Proteins