Isabelle Jupin

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RNA 3 of the beet necrotic yellow vein virus (BNYVV) quadripartite RNA genome is not essential for virus multiplication on leaves of Tetragonia expansa but has dramatic effects on symptom expression. Virus isolates containing RNA 3 produce bright yellow local lesions while isolates lacking RNA 3 produce much milder symptoms. Using directed mutagenesis of(More)
Virus-induced gene silencing (VIGS) is an important tool for the analysis of gene function in plants. This technique exploits recombinant viral vectors harbouring fragments of plant genes in their genome to generate double-stranded RNAs that initiate homology-dependent silencing of the target gene. Several viral VIGS vectors have already been successfully(More)
Tomato yellow leaf curl virus (TYLCV) is a whitefly-transmitted geminivirus with a monopartite genome. We have investigated the functions of the V1, V2, and C2 ORFs by mutational analysis. We analyzed the ability of TYLCV mutants containing disrupted ORFs V1, V2, or C2 to replicate, spread, and cause symptoms in Nicotiana benthamiana and tomato plants. All(More)
Transcription from the as-1 element of the cauliflower mosaic virus is induced by salicylic acid (SA), an endogenous signal involved in plant defence responses. Electrophoretic mobility shift assays demonstrated that the binding of a tobacco cellular factor, named SARP, correlates with the SA-induced activation of transcription. SARP was shown to contain(More)
Replication of positive-strand RNA viruses, the largest group of plant viruses, is initiated by viral RNA-dependent RNA polymerase (RdRp). Given its essential function in viral replication, understanding the regulation of RdRp is of great importance. Here, we show that Turnip yellow mosaic virus (TYMV) RdRp (termed 66K) is degraded by the proteasome at late(More)
Replication of the single-stranded DNA genome of plant geminiviruses follows a rolling circle mechanism. It strictly depends on a 'replication initiator protein' (Rep) which is the sole viral protein essential for replication. Rep protein catalyzes multiple reactions during the reproductive cycle of the virus. Here we summarize the recent advances of in(More)
Turnip yellow mosaic virus (TYMV), a positive-strand RNA virus belonging to the alphavirus-like supergroup, encodes its nonstructural replication proteins as a 206K precursor with domains indicative of methyltransferase (MT), proteinase (PRO), NTPase/helicase (HEL), and polymerase (POL) activities. Subsequent processing of 206K generates a 66K protein(More)
Over the last few decades, posttranslational modification of proteins by the addition of ubiquitin (Ub) and degradation by the Ubiquitin proteasome system (UPS) has emerged as a critical regulatory process in virtually all aspects of cell biology, including host /pathogen interactions. Recent findings point to the importance of Ub-related pathways during(More)
Turnip yellow mosaic virus (TYMV) encodes a 206-kDa (206K) polyprotein with domains of methyltransferase, proteinase, NTPase/helicase, and RNA-dependent RNA polymerase (RdRp). In vitro, the 206K protein has been shown to undergo proteolytic processing, giving rise to the synthesis of 140-kDa (140K) and 66-kDa (66K) proteins, the latter comprising the RdRp(More)
Tomato yellow leaf curl virus (TYLCV) is a whitefly-transmitted geminivirus with a monopartite genome. We have investigated the ability of a TYLCV DNA mutant containing a disrupted ORF C4 to infect Nicotiana benthamiana and tomato plants. The mutant retained the capability of autonomous replication in protoplast-derived cells of tomato and was able to(More)