|
|
|
|
|
| Jemaa, Mohamed; Morin, Nathalie; Cavelier, Patricia; Cau, Julien; Strub, Jean Marc; Delsert, Claude. |
| Long-lived animals show a non-observable age-related decline in immune defense, which is provided by blood cells that derive from self-renewing stem cells. The oldest living animals are bivalves. Yet, the origin of hemocytes, the cells involved in innate immunity, is unknown in bivalves and current knowledge about mollusk adult somatic stem cells is scarce. Here we identify a population of adult somatic precursor cells and show their differentiation into hemocytes. Oyster gill contains an as yet unreported irregularly folded structure (IFS) with stem-like cells bathing into the hemolymph. BrdU labeling revealed that the stem-like cells in the gill epithelium and in the nearby hemolymph replicate DNA. Proliferation of this cell population was further... |
| Tipo: Text |
Palavras-chave: Hematopoiesis; Adult somatic progenitor cells; Hemocytes; Mollusk; Marine invertebrates. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00197/30802/29172.pdf |
| |
|
|
| Cavelier, Patricia; Cau, Julien; Morin, Nathalie; Delsert, Claude. |
| While our knowledge of bivalve gametogenesis has progressed in recent times, more molecular markers are needed in order to develop tissue imaging. Here, we identified stem cell and mitotic markers to further characterize oyster early gametogenesis, mainly through immunofluorescence microscopy. Intense alkaline phosphatase activity, a non-specific marker for stem cells, was detected on the outer edge of the gonad ducts at the post-spawning stage, suggesting an abundance of undifferentiated cells very early during the sexual cycle. This observation was confirmed using an antibody against Sox2, a transcription factor specific for stem or germline cells, which labeled cells in the gonad duct inner mass and ciliated epithelium early during the initial oyster... |
| Tipo: Text |
Palavras-chave: Germline cells; Cell cycle; Reproduction; Bivalve; Marine invertebrates. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00409/52100/52809.pdf |
| |
|
|
| Delsert, Claude; Morin, Nathalie; Comps, Michel. |
| In this study, Dicentrarchus labrax encephalitis virus (DIEV), which causes sea bass encephalitis, was propagated in cell culture, thus allowing study of its lytic cycle, DIEV infection of mammalian and fish cells induced different patterns of expression of capsid proteins, which were assembled as virus-like particles, accumulating in the cytoplasm either as diffuse masses or in vesicles, as shown by electron microscopy, These particles correspond to virions, as shown by their ability to induce Secondary infection, Fish cells proved to be more permissive for DIEV than mammalian cells, although virus yield remained low, RNA analysis of infected sea bass cells revealed DIEV RNA3, in addition to genomic RNA1 and RNA2, and the presence of the RNA;! minus... |
| Tipo: Text |
|
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00336/44697/44983.pdf |
| |
|
|
| Van Dijk, Juliette; Bompard, Guillaume; Cau, Julien; Kunishima, Shinji; Rabeharivelo, Gabriel; Mateos-langerak, Julio; Cazevieille, Chantal; Cavelier, Patricia; Boizet-bonhoure, Brigitte; Delsert, Claude; Morin, Nathalie. |
| Background Upon maturation in the bone marrow, polyploid megakaryocytes elongate very long and thin cytoplasmic branches called proplatelets. Proplatelets enter the sinusoids blood vessels in which platelets are ultimately released. Microtubule dynamics, bundling, sliding, and coiling, drive these dramatic morphological changes whose regulation remains poorly understood. Microtubule properties are defined by tubulin isotype composition and post-translational modification patterns. It remains unknown whether microtubule post-translational modifications occur in proplatelets and if so, whether they contribute to platelet formation. Results Here, we show that in proplatelets from mouse megakaryocytes, microtubules are both acetylated and polyglutamylated. To... |
| Tipo: Text |
Palavras-chave: Microtubules; Acetylation; Polyglutamylation; Tubulin isotype; Platelets; Megakaryocytes; IIb3 integrin; CHO cells. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00463/57463/59577.pdf |
| |
|
|
| Van Dijk, Juliette; Bompard, Guillaume; Rabeharivelo, Gabriel; Cau, Julien; Delsert, Claude; Morin, Nathalie. |
| Mature megakaryocytes extend long processes called proplatelets from which platelets are released in the blood stream. The Rho GTPases Cdc42 and Rac as well as their downstream target, p21-activated kinase 2 (PAK2), have been demonstrated to be important for platelet formation. Here we address the role, during platelet formation, of PAK1, another target of the Rho GTPases. PAK1 decorates the bundled microtubules (MTs) of megakaryocyte proplatelets. Using a validated cell model which recapitulates proplatelet formation, elongation and platelet release, we show that lack of PAK1 activity increases the number of proplatelets but restrains their elongation. Moreover, in the absence of PAK1 activity, cells have hyperacetylated MTs and lose their MT network... |
| Tipo: Text |
Palavras-chave: Microtubules; Acetylation; Megakaryocytes; Proplatelet; P21-activated kinase 1 PAK1; Acetyltransferase MEC-17. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00654/76594/77743.pdf |
| |
|
|
| Bompard, Guillaume; Rabeharivelo, Gabriel; Frank, Marie; Cau, Julien; Delsert, Claude; Morin, Nathalie. |
| Ran is an essential GTPase that controls nucleocytoplasmic transport, mitosis, and nuclear envelope formation. These functions are regulated by interaction of Ran with different partners, and by formation of a Ran-GTP gradient emanating from chromatin. Here, we identify a novel level of Ran regulation. We show that Ran is a substrate for p21-activated kinase 4 (PAK4) and that its phosphorylation on serine-135 increases during mitosis. The endogenous phosphorylated Ran and active PAK4 dynamically associate with different components of the microtubule spindle during mitotic progression. A GDP-ound Ran phosphomimetic mutant cannot undergo RCC1-mediated GDP/GTP exchange and cannot induce microtubule asters in mitotic Xenopus egg extracts. Conversely,... |
| Tipo: Text |
|
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00014/12502/9353.pdf |
| |
|
|
| Wu, Chuan-fen; Delsert, Claude; Faure, Sandrine; Traverso, Edwin E.; Kloc, Malgorzata; Kuang, Jian; Etkin, Laurence D.; Morin, Nathalie. |
| Tumorhead (TH) regulates neural plate cell proliferation during Xenopus early development, and gain or loss of function prevents neural differentiation. TH shuttles between the nuclear and cytoplasmic/cortical cell compartments in embryonic cells. In this study, we show that subcellular distribution of TH is important for its functions. Targeting TH to the cell cortex/membrane potentiates a TH gain of function phenotype and results in neural plate expansion and inhibition of neuronal differentiation. We have found that TH subcellular localization is regulated, and that its shuttling between the nucleus and the cell cortex/cytoplasm is controlled by the catalytic activity of p21-activated kinase, X-PAK1. The phenotypes of embryos that lack, or have excess,... |
| Tipo: Text |
Palavras-chave: Actin cytoskeleton; Differentiation; Proliferation; Neural plate; P21 activated kinase; Tumorhead. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2996.pdf |
| |
|
|
|
