A new plant protein interacts with eIF3 and 60S to enhance virus-activated translation re-initiation.

Full 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.

Author information

Author/s: Thiébeauld, Odon (O); Schepetilnikov, Mikhail (M); Park, Hyun-Sook (HS); Geldreich, Angèle (A); Kobayashi, Kappei (K); Keller, Mario (M); Hohn, Thomas (T); Ryabova, Lyubov A (LA);

Affiliation: Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg Cedex, France.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: The EMBO journal (EMBO J), published in England. (Language: eng)

Reference: 2009-Oct; vol 28 (issue 20) : pp 3171-84

Dates: Created 2009/10/21; Completed 2009/11/03;

PMID: 19745810, status: MEDLINE (last retrieval date: 11/3/2009, IMS Date: )

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