P6 protein of Cauliflower mosaic virus, a translation reinitiator, interacts with ribosomal protein L13 from Arabidopsis thaliana

Bureau, Marina; Leh, Véronique; Haas, Muriel; Geldreich, Angèle; Ryabova, Lyubov A.; Yot, P.; Keller, Mario

doi:10.1099/vir.0.80242-0

Cited by 47 publications

(38 citation statements)

References 41 publications

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“…The subcellular localization in BY-2 cells of mutant EGFP:Am ( Figure 8B, panels 3 and 4), in which the three Leu residues of I1 were replaced by polar residues, was similar to that observed with EGFP:ADI1 ( Figure 8B, panels 1 and 2); EGFP:Am was found in both the cytoplasm and in the nucleus but not in the nucleolus. The absence of both EGFP:A mutants in the nucleolus, in contrast with the situation with EGFP:P6DI1 and EGFP:P6 point mutated versions (Figure 5), might be due to the fact that the N-terminal region of P6 is unable to interact with ribosomal proteins, whereas the EGFP:P6 mutants still contain the corresponding interaction domains (i.e., mini-TAV and RNA binding domain A) Park et al, 2001;Bureau et al, 2004).…”

Section: P6 Is a Nucleocytoplasmic Shuttling Proteinmentioning

confidence: 87%

“…On the other hand, we cannot totally exclude the possibilities that some of the interactions detected in yeast by Li and Leisner (2002) might be mediated by yeast RNA or proteins. Indeed, domains of P6 identified by these authors to be involved in P6-P6 interactions have nucleic acid binding properties and/or interact with cellular proteins, in particular nuclear-localized proteins (Park et al, 2001;Bureau et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…Park et al (2001) demonstrated that P6 is a translational reinitiation factor that associates with the host translational machinery and thus permits translation of downstream ORFs. This function is mediated by physical interactions between an internal region, including the minimal sequence of P6 required for transactivation (the mini-TAV; De Tapia et al, 1993), the initiation factor eIF3 (Park et al, 2001), and the ribosomal proteins L13 (Bureau et al, 2004), L18 , and L24 (Park et al, 2001). The observed interaction between P6 and the CaMV capsid protein (P4) also suggests a role for P6 as a scaffolding protein in the assembly of CaMV particles (Himmelbach et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

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The Open Reading Frame VI Product ofCauliflower mosaic virusIs a Nucleocytoplasmic Protein: Its N Terminus Mediates Its Nuclear Export and Formation of Electron-Dense Viroplasms

et al. 2005

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The Cauliflower mosaic virus (CaMV) open reading frame VI product (P6) is essential for the viral infection cycle. It controls translation reinitiation of the viral polycistronic RNAs and forms cytoplasmic inclusion bodies (viroplasms) where virus replication and assembly occur. In this study, the mechanism involved in viroplasm formation was investigated by in vitro and in vivo experiments. Far protein gel blot assays using a collection of P6 deletion mutants demonstrated that the N-terminal a-helix of P6 mediates interaction between P6 molecules. Transient expression in tobacco (Nicotiana tabacum) BY-2 cells of full-length P6 and P6 mutants fused to enhanced green fluorescent protein revealed that viroplasms are formed at the periphery of the nucleus and that the N-terminal domain of P6 is an important determinant in this process. Finally, this study led to the unexpected finding that P6 is a nucleocytoplasmic shuttle protein and that its nuclear export is mediated by a Leu-rich sequence that is part of the a-helix domain implicated in viroplasm formation. The discovery that P6 can localize to the nucleus opens new prospects for understanding yet unknown roles of this viral protein in the course of the CaMV infection cycle.

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Section: P6 Is a Nucleocytoplasmic Shuttling Proteinmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Open Reading Frame VI Product ofCauliflower mosaic virusIs a Nucleocytoplasmic Protein: Its N Terminus Mediates Its Nuclear Export and Formation of Electron-Dense Viroplasms

et al. 2005

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“…P1 may mediate the recruitment of the 60S subunits to the viral translation initiation complex. CaMV P6 protein has also been shown to localize in the nucleolus and interact with structural components of the 60S ribosome subunit (46,63,64). CaMV P6 is thought to transactivate translation of the viral polycistronic pregenomic RNA and its spliced versions.…”

Section: Discussionmentioning

confidence: 99%

Tobacco etch virus Protein P1 Traffics to the Nucleolus and Associates with the Host 60S Ribosomal Subunits during Infection

Martínez

Daròs

2014

J Virol

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The genus Potyvirus comprises a large group of positive-strand RNA plant viruses whose genome encodes a large polyprotein processed by three viral proteinases. P1 protein, the most amino-terminal product of the polyprotein, is an accessory factor stimulating viral genome amplification whose role during infection is not well understood. We infected plants with Tobacco etch virus (TEV; genus Potyvirus) clones in which P1 was tagged with a fluorescent protein to track its expression and subcellular localization or with an affinity tag to identify host proteins involved in complexes in which P1 also takes part during infection. Our results showed that TEV P1 exclusively accumulates in infected cells at an early stage of infection and that the protein displays a dynamic subcellular localization, trafficking in and out of the nucleus and nucleolus during infection. Inside the nucleolus, P1 particularly targets the dense granular component. Consistently, we found functional nucleolar localization and nuclear export signals in TEV P1 sequence. Our results also indicated that TEV P1 physically interacts with the host 80S cytoplasmic ribosomes and specifically binds to the 60S ribosomal subunits during infection. In vitro translation assays of reporter proteins suggested that TEV P1 stimulates protein translation, particularly when driven from the TEV internal ribosome entry site. These in vitro assays also suggested that TEV helper-component proteinase (HC-Pro) inhibits protein translation. Based on these findings, we propose that TEV P1 stimulates translation of viral proteins in infected cells. IMPORTANCEIn this work, we researched the role during infection of tobacco etch virus P1 protease. P1 is the most mysterious protein of potyviruses, a relevant group of RNA viruses infecting plants. Our experiments showed that the viral P1 protein exclusively accumulates in infected cells at an early stage of infection and moves in and out of the nucleus of infected cells, particularly targeting the nucleolus. Our experiments also showed that P1 protein binds host ribosomes during infection. Based on these findings and other in vitro experiments we propose that P1 protein stimulates translation of viral proteins during infection.

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“…To carry out this function, the P6 protein physically interacts with the initiation factor eIF3 (Park et al, 2001), as well as ribosomal proteins L13 (Bureau et al, 2004), L18 (Leh et al, 2000), and L24 (Park et al, 2001). Finally, P6 is also a nucleocytoplasmic shuttle protein whose nuclear export is dependent upon a Leu-rich sequence near its N terminus, a region that is also involved in inclusion body formation (Li and Leisner, 2002;Haas et al, 2005).…”

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confidence: 99%

The Cauliflower Mosaic Virus Protein P6 Forms Motile Inclusions That Traffic along Actin Microfilaments and Stabilize Microtubules

et al. 2008

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The gene VI product (P6) of Cauliflower mosaic virus (CaMV) is a multifunctional protein known to be a major component of cytoplasmic inclusion bodies formed during CaMV infection. Although these inclusions are known to contain virions and are thought to be sites of translation from the CaMV 35S polycistronic RNA intermediate, the precise role of these bodies in the CaMV infection cycle remains unclear. Here, we examine the functionality and intracellular location of a fusion between P6 and GFP (P6-GFP). We initially show that the ability of P6-GFP to transactivate translation is comparable to unmodified P6. Consequently, our work has direct application for the large body of literature in which P6 has been expressed ectopically and its functions characterized. We subsequently found that P6-GFP forms highly motile cytoplasmic inclusion bodies and revealed through fluorescence colocalization studies that these P6-GFP bodies associate with the actin/endoplasmic reticulum network as well as microtubules. We demonstrate that while P6-GFP inclusions traffic along microfilaments, those associated with microtubules appear stationary. Additionally, inhibitor studies reveal that the intracellular movement of P6-GFP inclusions is sensitive to the actin inhibitor, latrunculin B, which also inhibits the formation of local lesions by CaMV in Nicotiana edwardsonii leaves. The motility of P6 along microfilaments represents an entirely new property for this protein, and these results imply a role for P6 in intracellular and cell-to-cell movement of CaMV.

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P6 protein of Cauliflower mosaic virus, a translation reinitiator, interacts with ribosomal protein L13 from Arabidopsis thaliana

Cited by 47 publications

References 41 publications

The Open Reading Frame VI Product ofCauliflower mosaic virusIs a Nucleocytoplasmic Protein: Its N Terminus Mediates Its Nuclear Export and Formation of Electron-Dense Viroplasms

The Open Reading Frame VI Product ofCauliflower mosaic virusIs a Nucleocytoplasmic Protein: Its N Terminus Mediates Its Nuclear Export and Formation of Electron-Dense Viroplasms

Tobacco etch virus Protein P1 Traffics to the Nucleolus and Associates with the Host 60S Ribosomal Subunits during Infection

The Cauliflower Mosaic Virus Protein P6 Forms Motile Inclusions That Traffic along Actin Microfilaments and Stabilize Microtubules

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