A new plant protein interacts with eIF3 and 60S to enhance virus-activated translation re-initiation.
EMBO J
; 28(20): 3171-84, 2009 Oct 21.
Article
de En
| MEDLINE
| ID: mdl-19745810
ABSTRACT
The plant viral re-initiation factor transactivator viroplasmin (TAV) activates translation of polycistronic mRNA by a re-initiation mechanism involving translation initiation factor 3 (eIF3) and the 60S ribosomal subunit (60S). QJ;Here, we report a new plant factor-re-initiation supporting protein (RISP)-that enhances TAV function in re-initiation. RISP interacts physically with TAV in vitro and in vivo. Mutants defective in interaction are less active, or inactive, in transactivation and viral amplification. RISP alone can serve as a scaffold protein, which is able to interact with eIF3 subunits a/c and 60S, apparently through the C-terminus of ribosomal protein L24. RISP pre-bound to eIF3 binds 40S, suggesting that RISP enters the translational machinery at the 43S formation step. RISP, TAV and 60S co-localize in epidermal cells of infected plants, and eIF3-TAV-RISP-L24 complex formation can be shown in vitro. These results suggest that RISP and TAV bridge interactions between eIF3-bound 40S and L24 of 60S after translation termination to ensure 60S recruitment during repetitive initiation events on polycistronic mRNA; RISP can thus be considered as a new component of the cell translation machinery.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Biosynthèse des protéines
/
Protéines virales
/
Caulimovirus
/
Régulation de l'expression des gènes végétaux
/
Protéines d'Arabidopsis
/
Facteur-3 d'initiation eucaryote
/
Grande sous-unité du ribosome des eucaryotes
Type d'étude:
Prognostic_studies
Langue:
En
Journal:
EMBO J
Année:
2009
Type de document:
Article
Pays d'affiliation:
France