Biomaterial Database

Cucumber mosaic virus 2b protein subcellular targets and interactions: their significance to RNA silencing suppressor activity. 2010

Inmaculada González, and Llucia Martínez, and Daria V Rakitina, and Mathew G Lewsey, and Félix A Atencio, and César Llave, and Natalia O Kalinina, and John P Carr, and Peter Palukaitis, and Tomás Canto

Centro de Investigaciones Biológicas, CIB, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain.

The RNA silencing suppressor activity of the 2b protein of Cucumber mosaic virus (CMV) has been variously attributed to its nuclear targeting, its interaction with and inhibition of Argonaute 1 (AGO1), or its ability to bind small RNAs in vitro. In addition, the 2b ortholog of Tomato aspermy virus forms aggregates and binds RNAs in vitro. We have further studied the relationships between CMV 2b protein silencing suppressor activity and its subcellular distribution, protein-protein interactions in vivo, and interactions with small interfering RNAs in vitro. To do this, we tagged the protein with fluorescent markers and showed that it retained suppressor activity. We showed that the 2b protein is present in the nucleolus and that it self-interacts and interacts with AGO1 and AGO4 in vivo. Using a battery of mutants, we showed that the putative nuclear localization signals and phosphorylation motif of the 2b protein are not required for self-interaction or for interaction with AGO proteins. The occurrence of neither of these interactions or of nucleolar targeting was sufficient to provide local silencing-suppression activity. In contrast, the ability of the 2b protein to bind small RNAs appears to be indispensable for silencing suppressor function.

UI	MeSH Term	Description	Entries
D008164	Luminescent Proteins	Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.	Bioluminescent Protein,Bioluminescent Proteins,Luminescent Protein,Photoprotein,Photoproteins,Protein, Bioluminescent,Protein, Luminescent,Proteins, Bioluminescent,Proteins, Luminescent
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D010940	Plant Proteins	Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which PLANT PROTEINS, DIETARY is available.	Plant Protein,Protein, Plant,Proteins, Plant
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D014026	Nicotiana	A plant genus of the family SOLANACEAE. Members contain NICOTINE and other biologically active chemicals; the dried leaves of Nicotiana tabacum are used for SMOKING.	Tobacco Plant,Nicotiana tabacum,Plant, Tobacco,Plants, Tobacco,Tobacco Plants
D014764	Viral Proteins	Proteins found in any species of virus.	Gene Products, Viral,Viral Gene Products,Viral Gene Proteins,Viral Protein,Protein, Viral,Proteins, Viral
D017799	Cucumovirus	A genus of plant viruses of the family BROMOVIRIDAE, which infect cucurbits and solanaceous plants. Transmission occurs via aphids in a non-persistent manner, and also via seeds. The type species Cucumber mosaic virus, a CUCUMOVIRUS, should not be confused with Cucumber green mottle mosaic virus, a TOBAMOVIRUS.	Cucumber mosaic virus,Cucumber mosaic viruses,Cucumoviruses
D018515	Plant Leaves	Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)	Plant Leaf,Leaf, Plant,Leave, Plant,Leaves, Plant,Plant Leave
D019913	Nuclear Localization Signals	Short, predominantly basic amino acid sequences identified as nuclear import signals for some proteins. These sequences are believed to interact with specific receptors at the NUCLEAR PORE.	Nuclear Localization Signal,NLS Peptide,Nuclear Localization Signal Peptide,NLS Peptides,Peptide, NLS,Peptides, NLS,Signal, Nuclear Localization,Signals, Nuclear Localization