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Boudour-Boucheker, N., Boulo, V., Charmantier-Daures, M., Grousset, E., Anger, K., Charmantier, G., et al. (2014). Differential distribution of V-type H+-ATPase and Na+/K+-ATPase in the branchial chamber of the palaemonid shrimp Macrobrachium amazonicum. Cell and Tissue Research, 357(1), 195–206.
Résumé: V-H+-ATPase and Na+/K+-ATPase were localized in the gills and branchiostegites of M. amazonicum and the effects of salinity on the branchial chamber ultrastructure and on the localization of transporters were investigated. Gills present septal and pillar cells. In freshwater (FW), the apical surface of pillar cells is amplified by extensive evaginations associated with mitochondria. V-H+-ATPase immunofluorescence was localized in the membranes of the apical evaginations and in clustered subapical areas of pillar cells, suggesting labeling of intracellular vesicle membranes. Na+/K+-ATPase labeling was restricted to the septal cells. No difference in immunostaining was recorded for both proteins according to salinity (FW vs. 25 PSU). In the branchiostegite, both V-H+-ATPase and Na+/K+-ATPase immunofluorescence were localized in the same cells of the internal epithelium. Immunogold revealed that V-H+-ATPase was localized in apical evaginations and in electron-dense areas throughout the inner epithelium, while Na+/K+-ATPase occurred densely along the basal infoldings of the cytoplasmic membrane. Our results suggest that morphologically different cell types within the gill lamellae may also be functionally specialized. We propose that, in FW, pillar cells expressing V-H+-ATPase absorb ions (Cl-, Na+) that are transported either directly to the hemolymph space or through a junctional complex to the septal cells, which may be responsible for active Na+ delivery to the hemolymph through Na+/K+-ATPase. This suggests a functional link between septal and pillar cells in osmoregulation. When shrimps are transferred to FW, gill and branchiostegite epithelia undergo ultrastructural changes, most probably resulting from their involvement in osmoregulatory processes.
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Desvignes, T., Nguyen, T., Chesnel, F., Bouleau, A., Fauvel, C., & Bobe, J. (2015). X-Linked Retinitis Pigmentosa 2 Is a Novel Maternal-Effect Gene Required for Left-Right Asymmetry in Zebrafish. Biol. Reprod., 93(2), 42.
Résumé: Retinitis pigmentosa 2 (RP2) gene is responsible for up to 20% of X-linked retinitis pigmentosa, a severe heterogeneous genetic disorder resulting in progressive retinal degeneration in humans. In vertebrates, several bodies of evidence have clearly established the role of Rp2 protein in cilia genesis and/or function. Unexpectedly, some observations in zebrafish have suggested the oocyte-predominant expression of the rp2 gene, a typical feature of maternal-effect genes. In the present study, we investigate the maternal inheritance of rp2 gene products in zebrafish eggs in order to address whether rp2 could be a novel maternal-effect gene required for normal development. Although both rp2 mRNA and corresponding protein are expressed during oogenesis, rp2 mRNA is maternally inherited, in contrast to Rp2 protein. A knockdown of the protein transcribed from both rp2 maternal and zygotic mRNA results in delayed epiboly and severe developmental defects, including eye malformations, that were not observed when only the protein from zygotic origin was knocked down. Moreover, the knockdown of maternal and zygotic Rp2 revealed a high incidence of left-right asymmetry establishment defects compared to only zygotic knockdown. Here we show that rp2 is a novel maternal-effect gene exclusively expressed in oocytes within the zebrafish ovary and demonstrate that maternal rp2 mRNA is essential for successful embryonic development and thus contributes to egg developmental competence. Our observations also reveal that Rp2 protein translated from maternal mRNA is important to allow normal heart loop formation, thus providing evidence of a direct maternal contribution to left-right asymmetry establishment.
Mots-Clés: developmental biology; egg developmental competence; egg quality; fish; fish reproduction; kupffers vesicle; left-right axis; linked retinitis-pigmentosa; maternal-effect gene; midblastula transition; molecular characterization; ndpk; nme10; oocyte; oocyte-specific; ovum; pigmentosa protein rp2; plasma-membrane; retinitis-pigmentosa-2 protein; teleost; to-zygotic transition; vertebrate development; zygote
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