The Lengthening of a Giant Protein: When, How, and Why?

Abstract Subcommissural organ (SCO)-spondin is a giant glycoprotein of more than 5000 amino acids found in Vertebrata, expressed in the central nervous system and constitutive of Reissner's fiber. For the first time, in situ hybridization performed on zebrafish (Danio rerio) embryos shows that the gene encoding this protein is expressed transitionally in the floor plate, the ventral midline of the neural tube, and later in the diencephalic third ventricle roof, the SCO. The modular organization of the protein in Echinodermata (Strongylocentrotus purpuratus), Urochordata (Ciona savignyi and C. intestinalis), and Vertebrata (Teleostei, Amphibia, Aves and Mammalia) is also described. As the thrombospondin type 1 repeat motifs represent an increasingly large part of the protein during Deuterostomia evolution, the duplication mechanisms leading to this complex organization are examined. The functional significance of the particularly well-preserved arrangement of the series of SCO-spondin repeat motifs and thombospondin type 1 repeats is discussed

Etude de cibles génomiques pour le développement d'un outil de diagnostic moléculaire universel des bactéries appliqué à l'étude de l'écosystème digestif

CLERMONT FD-BCIU-Santé (631132104) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

The lengthening of a giant protein: When, how, and why?

International audienceSubcommissural organ (SCO)-spondin is a giant glycoprotein of more than 5000 amino acids found in Vertebrata, expressed in the central nervous system and constitutive of Reissner’s fiber. For the first time, in situ hybridization performed on zebrafish (Danio rerio) embryos shows that the gene encoding this protein is expressed transitionally in the floor plate, the ventral midline of the neural tube, and later in the diencephalic third ventricle roof, the SCO. The modular organization of the protein in Echinodermata (Strongylocentrotus purpuratus), Urochordata (Ciona savignyi and C. intestinalis), and Vertebrata (Teleostei, Amphibia, Aves and Mammalia) is also described. As the thrombospondin type 1 repeat motifs represent an increasingly large part of the protein during Deuterostomia evolution, the duplication mechanisms leading to this complex organization are examined. The functional significance of the particularly well-preserved arrangement of the series of SCO-spondin repeat motifs and thombospondin type 1 repeats is discussed

Drosophila melanogaster P-glycoprotein : A membrane detoxification system toward polycyclic aromatic hydrocarbon pollutants

International audiencePolycyclic aromatic hydrocarbons (PAHs) are well-known ubiquitous environmental contaminants. Permeability glycoprotein (P-gp) is a transmembrane detoxification efflux pump transporting various lipophilic xenobiotics, such as PAHs, out of the cells. The existence of a P-gp detoxification system inducible by PAHs was investigated in Drosophila melanogaster. Western blot experiments showed that D. melanogaster expressed a 140-kDa P-gp in S12 cells, embryos, and adult flies. Permeability glycoprotein was expressed in adult flies in the head, abdomen, and thorax and sublocalized in the sexual and olfactory organs. Flow cytometry experiments using Drosophila S12 cells in the presence of PAHs and target P-gp drug compounds revealed that Drosophila P-gp acted as an efflux detoxification pump. In Drosophila exposed to benzo[a]pyrene or to ambient air polluted by higher or lower PAH concentrations, P-gp expression was clearly showed a dose-dependent increase response. The P-gp induction was detected both in adult flies and in different fly parts, such as the head, thorax, and antennae. Drosophila P-gp acts as a membrane barrier against PAH pollutants