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Neuhaus, Jean-Marc
Nom
Neuhaus, Jean-Marc
Affiliation principale
Fonction
Professeur ordinaire
Email
jean-marc.neuhaus@unine.ch
Identifiants
Résultat de la recherche
Voici les éléments 1 - 6 sur 6
- PublicationAccès libreExpression of a glycosylated GFP as a bivalent reporter in exocytosis(2010)
; Di Sansebastiano, Gian PietroThe complex-type N-linked glycans of plants differ markedly in structure from those of animals. Like those of insects and mollusks they lack terminal sialic acid(s) and may contain an α-(1,3)-fucose (Fuc) linked to the proximal GlcNAc residue and/or a β-(1,2)-xylose (Xyl) residue attached to the proximal mannose (Man) of the glycan core. N-glycosylated GFPs were used in previous studies showing their effective use to report on membrane traffic between the ER and the Golgi apparatus in plant cells. In all these cases glycosylated tags were added at the GFP termini. Because of the position of the tag and depending on the sorting and accumulation site of these modified GFP, there is always a risk of processing and degradation, and this protein design cannot be considered ideal. Here, we describe the development of three different GFPs in which the glycosylation site is internally localized at positions 80, 133, or 172 in the internal sequence. The best glycosylation site was at position 133. This glycosylated GFPgl133 appears to be protected from undesired processing of the glycosylation site and represents a bivalent reporter for biochemical and microscopic studies. After experimental validation, we can conclude that amino acid 133 is an effective glycosylation site and that the GFPgl133 is a powerful tool for in vivo investigations in plant cell biology. - PublicationAccès libreRegeneration of a Lytic Central Vacuole and of Neutral Peripheral Vacuoles Can Be Visualized by Green Fluorescent Proteins Targeted to Either Type of Vacuoles(2001)
; Protein trafficking to two different types of vacuoles was investigated in tobacco (Nicotiana tabacum cv SR1) mesophyll protoplasts using two different vacuolar green fluorescent proteins (GFPs). One GFP is targeted to a pH-neutral vacuole by the C-terminal vacuolar sorting determinant of tobacco chitinase A, whereas the other GFP is targeted to an acidic lytic vacuole by the N-terminal propeptide of barley aleurain, which contains a sequence-specific vacuolar sorting determinant. The trafficking and final accumulation in the central vacuole (CV) or in smaller peripheral vacuoles differed for the two reporter proteins, depending on the cell type. Within 2 d, evacuolated (mini-) protoplasts regenerate a large CV. Expression of the two vacuolar GFPs in miniprotoplasts indicated that the newly formed CV was a lytic vacuole, whereas neutral vacuoles always remained peripheral. Only later, once the regeneration of the CV was completed, the content of peripheral storage vacuoles could be seen to appear in the CV of a third of the cells, apparently by heterotypic fusion. - PublicationMétadonnées seulementRegeneration of a lytic central vacuole and of neutral peripheral vacuoles can be visualized by green fluorescent proteins targeted to either type of vacuoles(2001)
; Protein trafficking to two different types of vacuoles was investigated in tobacco (Nicotiana tabacum cv SR1) mesophyll protoplasts using two different vacuolar green fluorescent proteins (GFPs). One GFP is targeted to a pH-neutral vacuole by the C-terminal vacuolar sorting determinant of tobacco chitinase A, whereas the other GFP is targeted to an acidic lytic vacuole by the N-terminal propeptide of barley aleurain, which contains a sequence-specific vacuolar sorting determinant. The trafficking and final accumulation in the central vacuole (CV) or in smaller peripheral vacuoles differed for the two reporter proteins, depending on the cell type. Within 2 d, evacuolated (mini-) protoplasts regenerate a large CV. Expression of the two vacuolar GFPs in miniprotoplasts indicated that the newly formed CV was a lytic vacuole, whereas neutral vacuoles always remained peripheral. Only later, once the regeneration of the CV was completed, the content of peripheral storage vacuoles could be seen to appear in the CV of a third of the cells, apparently by heterotypic fusion. - PublicationAccès libreSubcellular localization and in vivo identification of the putative movement protein of olive latent virus 2(1999)
; Martelli, Giovanni P.The gene encoding the 36.5 kDa ('36K') nonstructural protein located on RNA3 of olive latent virus 2 (OLV-2) was cloned, expressed with the Escherichia coli pGEX-2T system and the purified protein used to raise a polyclonal antiserum. Immunoblot analysis of OLV-2-infected Nicotiana benthamiana plants showed that the 36K protein accumulated in the early stages of infection and was associated with a subcellular fraction enriched in cytoplasmic membranes. In infected cells there were tubular structures, some containing virus-like particles, scattered in the cytoplasm or protruding from or penetrating the cell wall at the plasmodesmata. Immunogold labelling localized the 36K protein in the plasmodesmata of OLV-2-infected cells and showed it to be associated with virus-containing tubules. Leaf trichome cells of N. tabacum plants, transformed with a 36K--green fluorescent protein (GFP) fusion construct, revealed localized fluorescence in the cell walls, possibly due to association of the fusion protein with plasmodesmata. When the same 36K--GFP fusion protein was expressed in N. tabacum protoplasts, long tubular fluorescent structures protruded from the protoplast surface, suggesting that the 36K protein is responsible for tubule induction. The conclusion is drawn that this protein is likely to be the OLV-2 movement protein, mediating cell-to-cell virus movement, and that movement is by a tubule-guided mechanism. - PublicationMétadonnées seulementSubcellular localization and in vivo identification of the putative movement protein of olive latent virus 2(1999)
; Martelli, Giovanni PThe gene encoding the 36.5 kDa ('36K') nonstructural protein located on RNA3 of olive latent virus 2 (OLV-2) was cloned, expressed with the Escherichia coli pGEX-2T system and the purified protein used to raise a polyclonal antiserum. Immunoblot analysis of OLV-2-infected Nicotiana benthamiana plants showed that the 36K protein accumulated in the early stages of infection and was associated with a subcellular fraction enriched in cytoplasmic membranes. In infected cells there were tubular structures, some containing virus-like particles, scattered in the cytoplasm or protruding from or penetrating the cell wall at the plasmodesmata, Immunogold labelling localized the 36K protein in the plasmodesmata of OLV-2-infected cells and showed it to be associated with virus-containing tubules, Leaf trichome cells of N. tabacum plants, transformed with a 36K-green fluorescent protein (GFP) fusion construct, revealed localized fluorescence in the cell walls, possibly due to association of the fusion protein with plasmodesmata, When the same 36K-GFP fusion protein was expressed in N. tabacum protoplasts, long tubular fluorescent structures protruded from the protoplast surface, suggesting that the 36K protein is responsible for tubule induction. The conclusion is drawn that this protein is likely to be the OLV-2 movement protein, mediating cell-to-cell virus movement, and that movement is by a tubule-guided mechanism. - PublicationAccès libreSpecific accumulation of GFP in a non-acidic vacuolar compartment via a C-terminal propeptide-mediated sorting pathway(1998)
; The green fluorescent protein (GFP) from Aequorea victoria can be detected in living plant cells after transient transformation of protoplasts. Expression of the GFP can be used to monitor protein trafficking in a mixed cell population and also to study the different function and importance of organelles in different cell types. We developed a vacuolar form of GFP that was obtained by replacing the C-terminal endoplasmic reticulum (ER)-retention motif of mGFP5-ER by the vacuolar targeting peptide of tobacco chitinase A. The vacuolar GFP was transported and accumulated in the vacuole as expected. However, we found two patterns of GFP accumulation after prolonged incubation (18–24 h) depending on the cell type. Most chloroplast-rich protoplasts had a fluorescent large central vacuole. In contrast, most chloroplast-poor protoplasts accumulated the GFP in one smaller vacuole but not in the large central vacuole, which was visible under a light microscope in the same cell. This differential accumulation reflected the existence of two different vacuolar compartments as described recently by immunolocalization of several vacuolar markers. We were able to characterize the vacuolar compartment to which GFP is specifically targeted as non-acidic, since it did not accumulate neutral red while acidic vacuoles did not accumulate GFP.