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

作者：Thiebeauld Odon; Schepetilnikov Mikhail; Park Hyun Sook; Geldreich Angele; Kobayashi Kappei; Keller Mario; Hohn Thomas; Ryabova Lyubov A^*

来源：The EMBO Journal, 2009, 28(20): 3171-3184.

DOI：10.1038/emboj.2009.256

• Cauliflower mosaic virus (CaMV)
• eIF3
• large ribosomal subunit (60S)
• re-initiation supporting protein (RISP)
• transactivator viroplasmin (TAV)

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. The EMBO Journal (2009) 28, 3171-3184. doi:10.1038/emboj.2009.256; Published online 10 September 2009

• 出版日期2009-10-21
• 单位河北医科大学