Measles virus N protein inhibits host translation by binding to eIF3-p40.
The nonsegmented, negative-sense RNA genome of measles virus (MV) is encapsidated by the virus-encoded nucleocapsid protein (N). In this study, we searched for N-binding cellular proteins by using MV-N as bait and screening the human T-cell cDNA library by yeast two-hybrid assay and isolated the p40 subunit of eukaryotic initiation factor 3 (eIF3-p40) as a binding partner. The interaction between MV-N and eIF3-p40 in mammalian cells was confirmed by coimmunoprecipitation. Since eIF3-p40 is a translation initiation factor, we analyzed the potential inhibitory effect of MV-N on protein synthesis. Glutathione S-transferase (GST)-fused MV-N (GST-N) inhibited translation of reporter mRNAs in rabbit reticulocyte lysate translation system in a dose-dependent manner. Encephalomyocarditis virus internal ribosomal entry site-mediated translation, which requires canonical initiation factors to initiate translation, was also inhibited by GST-N. In contrast, a unique form of translation mediated by the intergenic region of Plautia stali intestine virus, which can assemble 80S ribosomes in the absence of canonical initiation factors, was scarcely affected by GST-N. In vivo expression of MV-N induced by the Cre/loxP switching system inhibited the synthesis of a transfected reporter protein, as well as overall protein synthesis. These results suggest that MV-N targets eIF3-p40 and may be involved in inhibiting MV-induced host translation.
Laboratory Animal Research Center, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
Hiroki
H
Sato
Munemitsu
M
Masuda
Moeko
M
Kanai
Kyoko
K
Tsukiyama-Kohara
Misako
M
Yoneda
Chieko
C
Kai
D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004305:Dose-Response Relationship, Drug; D004686:Encephalomyocarditis virus / Q000378:metabolism; D039621:Eukaryotic Initiation Factor-3 / Q000737:chemistry*; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008459:Measles virus / Q000378:metabolism*; D019590:Nucleocapsid Proteins / Q000378:metabolism / Q000502:physiology*; D011485:Protein Binding; D014176:Protein Biosynthesis; D011817:Rabbits; D012270:Ribosomes / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D039621:Eukaryotic Initiation Factor-3; D019590:Nucleocapsid Proteins; D005982:Glutathione Transferase