title: The NS3 protein of rice hoja blanca virus complements the RNAi suppressor function of HIV-1 Tat.
abstract: The question of whether RNA interference (RNAi) acts as an antiviral mechanism in mammalian cells remains controversial. The antiviral interferon (IFN) response cannot easily be distinguished from a possible antiviral RNAi pathway owing to the involvement of double-stranded RNA (dsRNA) as a common inducer molecule. The non-structural protein 3 (NS3) protein of rice hoja blanca virus (RHBV) is an RNA silencing suppressor (RSS) that exclusively binds to small dsRNA molecules. Here, we show that this plant viral RSS lacks IFN antagonistic activity, yet it is able to substitute the RSS function of the Tat protein of human immunodeficiency virus type 1. An NS3 mutant that is deficient in RNA binding and its associated RSS activity is inactive in this complementation assay. This cross-kingdom suppression of RNAi in mammalian cells by a plant viral RSS indicates the significance of the antiviral RNAi response in mammalian cells and the usefulness of well-defined RSS proteins.
authors.affiliation: Laboratory of Virology, Wageningen University, Binnenhaven 11, 6709 PD Wageningen, The Netherlands.
authors.forename: Esther
authors.initials: E
authors.lastname: Schnettler
authors.forename: Walter
authors.initials: W
authors.lastname: de Vries
authors.forename: Hans
authors.initials: H
authors.lastname: Hemmes
authors.forename: Joost
authors.initials: J
authors.lastname: Haasnoot
authors.forename: Richard
authors.initials: R
authors.lastname: Kormelink
authors.forename: Rob
authors.initials: R
authors.lastname: Goldbach
authors.forename: Ben
authors.initials: B
authors.lastname: Berkhout
mesh_terms: D000818:Animals; D002460:Cell Line; D006801:Humans; D012275:Oryza / Q000821:virology*; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D029364:Tenuivirus / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism*
chemical_list: D012330:RNA, Double-Stranded; D014764:Viral Proteins; D054322:tat Gene Products, Human Immunodeficiency Virus