Variabilité génétique de la lignification et de la digestibilité des hampes florales dans une descendance recombinante d'Arabidopsis thaliana, plante modèle pour le maïs et les graminées fourragères

il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : DISSERTATIONVariabilité génétique de la lignification et de la digestibilité des hampes florales dans une descendance recombinante d'[i]Arabidopsis thaliana[/i], plante modèle pour le maïs et les graminées fourragère

Autophagy mediates phosphatidylserine exposure and phagosome degradation during apoptosis through specific functions of GABARAP/LGG-1 and LC3/LGG-2

International audiencePhagocytosis and macroautophagy/autophagy are 2 processes involved in lysosome-mediated clearance of extracellular and intracellular components, respectively. Recent studies have identified the recruitment of the autophagic protein LC3 during phagocytosis of apoptotic corpses in what is now called LC3-associated phagocytosis (LAP). LAP is a distinct process from autophagy but it relies on some members of the autophagy pathway to allow efficient degradation of the phagocytosed cargo. We investigated whether both LC3/LGG-2 and GABARAP/LGG-1 are involved in phagocytosis of apoptotic corpses during embryonic development of Caenorhabditis elegans. We discovered that both LGG-1 and LGG-2 are involved in the correct elimination of apoptotic corpses, but that they have different functions. lgg-1 and lgg-2 mutants present a delay in phagocytosis of apoptotic cells but genetic analyses indicate that LGG-1 and LGG-2 act upstream and downstream of the engulfment pathways, respectively. Moreover, LGG-1 and LGG-2 display different cellular localizations with enrichment in apoptotic corpses and phagocytic cells, respectively. For both LGG-1 and LGG-2, subcellular localization is vesicular and dependent on UNC-51/ULK1, BEC-1/BECN1 and the lipidation machinery, indicating that their functions during phagocytosis of apoptotic corpses mainly rely on autophagy. Finally, we show that LGG-1 is involved in the exposure of the 'eat-me signal' phosphatidylserine at the surface of the apoptotic cell to allow its recognition by the phagocytic cell, whereas LGG-2 is involved in later steps of phagocytosis to allow efficient cell corpse clearance by mediating the maturation/degradation of the phagosome

Lipopolythiourea Transfecting Agents: Lysine Thiourea Derivatives

International audienceSynthetic vectors represent an alternative to recombinant viruses for gene transfer. We have recently explored the transfection potential of a class of noncationic lipids bearing thiourea moieties as DNA associating headgroups. The encouraging results obtained with lipopolythioureas derived from serinol prompted us to investigate further this family of vectors. In the present study, we considered the transfection properties of a series of derivatives based on a different thiourea polar headgroup bearing a lysine scaffold. The synthesis of these compounds could be readily achieved in 3 steps with good yields. We found that these lipopolythioureas (LPT) might be considered as alternative systems for gene transfection, since their activity reached the same magnitude range as cationic vectors in the presence of serum. LPT with 14-carbon length chains appeared to be more efficient as transfecting agent than the ones with shorter chains. Toxicity studies proved that the hydration film 2 method led to particles well tolerated both by the cells in vitro and by the mice in vivo. The ability to induce gene expression in vivo was demonstrated by intratumoral injection. Finally, biodistribution studies showed that the quantity recovered in the blood circulation, 2h after systemic injection, was improved as compared to cationic lipids

Design, Synthesis, and Evaluation of Enhanced DNA Binding New Lipopolythioureas

International audienceNonviral gene delivery is limited to a large extent by the cationic nature of most of the chemical vector. We have shown that lipopolythioureas interact with DNA. However, lipopolythioureas were not very efficient at transfecting cells, probably due to reduced interaction between the noncationic synthetic lipid and the cell membrane. Here, we report that liposomes made from a new thiourea lipid, DPPC, and a lipid bearing an RGD ligand allowed very efficient entry of the lipopolythioureas into integrin R v 3 expressing cells. In addition, we show that a stable interaction between DNA and lipopolythiourea could be obtain with two thiourea groups. Moreover, the addition of a hydrophilic terminus improves the formulation of these new DNA binding agents