2FNC1†Dedicated to Rob Goldbach who sadly passed away on 7 April 009.
2FNC‡Present address: Rockefeller University, Laboratory of Plant Molecular Biology, 130 York Avenue, New York, NY 10065, USA.
2FNC3§Present address: Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences & University Medical Centre Utrecht, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
2FNC4||Present address: Keygene N.V., Agro Business Park 90, 6708 PW Wageningen, The Netherlands.
The NS3 protein of rice hoja blanca virus represents a viral suppressor of RNA interference (RNAi) that sequesters small interfering (si)RNAs in vitro. To determine whether this siRNA binding property is the critical determinant for the suppressor activity of NS3, NS3 was altered by alanine point mutations and the resulting mutant proteins were tested for both siRNA binding ability and RNAi suppressor activity in plants. Alanine substitutions of lysine residues at positions 173–175 resulted in mutant proteins that lost both their affinity for siRNAs and their RNAi suppressor activity in planta. This indicates that siRNA binding of NS3 is indeed essential for the suppressor function of NS3 and that residues at positions 173–175 are involved in the siRNA binding and suppressor activities.
BucherE.,
SijenT.,
de HaanP.,
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HemmesH.,
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NicholS. T.2004; A C-terminal basic amino acid motif of Zaire ebolavirus VP35 is essential for type I interferon antagonism and displays high identity with the RNA-binding domain of another interferon antagonist, the NS1 protein of influenza A virus. Virology 328:177–184[CrossRef]
HemmesH.,
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BurgyánJ.,
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LynchP.,
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KrugR. M.1999; RNA binding by the novel helical domain of the influenza virus NS1 protein requires its dimer structure and a small number of specific basic amino acids. RNA 5:195–205[CrossRef]