214,900 research outputs found
Hommages du GERM (24/06) : Cérémonie de remerciement à M. et Mme. Laborde
No full textLe 24 juin 2014, à 17h Cérémonie de remerciement à M. et Mme. Laborde, lesquels ont généreusement fait don d'un important fonds d'ouvrage sur la Mésoamérique. Ce fonds, donné à la Société des Américanistes, est déposé à la Bibliothèque d'ethnologie Eric-de-Dampierre (MAE, Nanterre) et nourrira les recherches des membres du GERM et de tous les étudiants et collègues intéressés. par la Mésomamérique. Nanterre: LESC, MAE salle 30
Publication GERM : "Millenary Maya Societies: Past Crises and Resilience"
No full textArnauld, M.-Charlotte and Alain Breton (éds). 2013 Millenary Maya Societies: Past Crises and Resilience Sociedades mayas milenarias: crisis del pasado y resiliencia Papers from the International Colloquium (Memorias del coloquio international) “Sociétés mayas millénaires: crises du passé et résilience” Musée du quai Branly Paris, July 1-2, 2011. 329 pp. Mesoweb | http://www.mesoweb.com/publications/MMS/ Télécharger le volume complet (80 MB) Page de titre, Sommaire et Introduction Chapter 1 Ti..
Colloque international “VARIANTES ET VARIATIONS EN PAYS MAYA”
No full textColloque international “Variantes et variations en pays maya” les 10, 11 et 12 décembre 2007 - Maison de l’archéologie et de l’ethnologie, Nanterre / Maison du Mexique, Cité Universitaire, Paris org. M.-Charlotte Arnauld, Alain Breton, Jacques Galinier, et Aurore Monod Becquelin). Les partenaires invitants étaient, par l'intermédiaire du GERM, le Centre National de la Recherche Scientifique (CNRS), le Ministère des Affaires Étrangères et Européennes (MAEE), le Musée du Quai Branly, la Cité U..
Séance du GERM (24/06) : "Donner à manger à la maison ..."
No full textLe 24 juin 2014, à 14h30 M-Charlotte Arnauld (ArchAm) "Donner à manger à la maison: architecture maçonnée et dépôts rituels" Un dépôt exceptionnellement riche en animaux de petite taille d’espèces aquatiques (eau de mer et eau douce) et arborées (oiseaux du groupe passereaux) a été trouvé au centre de l’Edifice 6E12Sub de La Joyanca (Guatemala) en 2003. Il a été fait au moment du remblaiement de la structure sur laquelle a été construite un temple sur son soubassement pyramidal, vers 750 apr..
The translational repressor Cup is required for germ plasm assembly and germ cell development in Drosophila.
No full textRNA localization is a cellular mechanism used to localize proteins to sub-cellular domains and to control protein synthesis regionally. In oocytes, RNA localization has profound implications for development, generating asymmetric protein distributions that promote morphological and functional cell polarization and establish regional fates in the future embryo. One such fate is that of the germ cell lineage.
In Drosophila, germ cell formation depends on maternal inherited factors localized in the posterior pole region of oocytes and early embryos, named germ plasm. Oskar (Osk), a key determinant of germ plasm assembly, is both necessary and sufficient for germ-line formation and posterior patterning The localization of oskar (osk) mRNA starts during oogenesis and it is mediated by trans-acting factors several of which have been shown to have roles in post-transcriptional regulation of RNA, such as splicing, translational control and degradation. However, most of the molecular mechanisms underlying osk mRNA localization are still unclear (Zhou Y. and King ML, 2004).
During the course of my study, I have demonstrated that Cup, a translational regulator of specific mRNAs, localizes to both nuage, a germ-line perinuclear organelle assembled during early oogenesis, and germ plasm. Moreover, Cup protein interacts with Osk and Vasa (Vas) to assure anchoring, stabilization and/or maintenance of germ plasm particles to the posterior pole of oocytes and early embryos. According to these results, homozygous cup mutant embryos display a reduced number of germ cells, respect to the heterozygous cup mutants. The latest embryos exhibit in turn less germ cells than wild type. Finally, cup and osk interact genetically, since reducing cup copy number further decreases the total number of germ cells observed in heterozygous osk mutant embryos. In this thesis, I shed light on a novel role of Cup during germ plasm assembly and germ cell development in Drosophila
Protein interactions in Xenopus germ plasm RNP particles
No full textHermes is an RNA-binding protein that we have previously reported to be found in the ribonucleoprotein (RNP) particles of Xenopus germ plasm, where it is associated with various RNAs, including that encoding the germ line determinant Nanos1. To further define the composition of these RNPs, we performed a screen for Hermes-binding partners using the yeast two-hybrid system. We have identified and validated four proteins that interact with Hermes in germ plasm: two isoforms of Xvelo1 (a homologue of zebrafish Bucky ball) and Rbm24b and Rbm42b, both RNA-binding proteins containing the RRM motif. GFP-Xvelo fusion proteins and their endogenous counterparts, identified with antisera, were found to localize with Hermes in the germ plasm particles of large oocytes and eggs. Only the larger Xvelo isoform was naturally found in the Balbiani body of previtellogenic oocytes. Bimolecular fluorescence complementation (BiFC) experiments confirmed that Hermes and the Xvelo variants interact in germ plasm, as do Rbm24b and 42b. Depletion of the shorter Xvelo variant with antisense oligonucleotides caused a decrease in the size of germ plasm aggregates and loosening of associated mitochondria from these structures. This suggests that the short Xvelo variant, or less likely its RNA, has a role in organizing and maintaining the integrity of germ plasm in Xenopus oocytes. While GFP fusion proteins for Rbm24b and 42b did not localize into germ plasm as specifically as Hermes or Xvelo, BiFC analysis indicated that both interact with Hermes in germ plasm RNPs. They are very stable in the face of RNA depletion, but additive effects of combinations of antisense oligos suggest they may have a role in germ plasm structure and may influence the ability of Hermes protein to effectively enter RNP particles
Identification of nine new susceptibility loci for testicular cancer, including variants near DAZL and PRDM14.
No full textTesticular germ cell tumor (TGCT) is the most common cancer in young men and is notable for its high familial risks. So far, six loci associated with TGCT have been reported. From genome-wide association study (GWAS) analysis of 307,291 SNPs in 986 TGCT cases and 4,946 controls, we selected for follow-up 694 SNPs, which we genotyped in a further 1,064 TGCT cases and 10,082 controls from the UK. We identified SNPs at nine new loci (1q22, 1q24.1, 3p24.3, 4q24, 5q31.1, 8q13.3, 16q12.1, 17q22 and 21q22.3) showing association with TGCT (P < 5 × 10(-8)), which together account for an additional 4-6% of the familial risk of TGCT. The loci include genes plausibly related to TGCT development. PRDM14, at 8q13.3, is essential for early germ cell specification, and DAZL, at 3p24.3, is required for the regulation of germ cell development. Furthermore, PITX1, at 5q31.1, regulates TERT expression and is the third TGCT-associated locus implicated in telomerase regulation
Localisation of RNAs into the germ plasm of vitellogenic xenopus oocytes
No full textWe have studied the localisation of mRNAs in full-grown Xenopus laevis oocytes by injecting fluorescent RNAs, followed by confocal microscopy of the oocyte cortex. Concentrating on RNA encoding the Xenopus Nanos homologue, nanos1 (formerly Xcat2), we find that it consistently localised into aggregated germ plasm ribonucleoprotein (RNP) particles, independently of cytoskeletal integrity. This implies that a diffusion/entrapment-mediated mechanism is active, as previously reported for previtellogenic oocytes. Sometimes this was accompanied by localisation into scattered particles of the “late”, Vg1/VegT pathway; occasionally only late pathway localisation was seen. The Xpat RNA behaved in an identical fashion and for neither RNA was the localisation changed by any culture conditions tested. The identity of the labelled RNP aggregates as definitive germ plasm was confirmed by their inclusion of abundant mitochondria and co-localisation with the germ plasm protein Hermes. Further, the nanos1/Hermes RNP particles are interspersed with those containing the germ plasm protein Xpat. These aggregates may be followed into the germ plasm of unfertilized eggs, but with a notable reduction in its quantity, both in terms of injected molecules and endogenous structures. Our results conflict with previous reports that there is no RNA localisation in large oocytes, and that during mid-oogenesis even germ plasm RNAs localise exclusively by the late pathway. We find that in mid oogenesis nanos1 RNA also localises to germ plasm but also by the late pathway. Late pathway RNAs, Vg1 and VegT, also may localise into germ plasm. Our results support the view that mechanistically the two modes of localisation are extremely similar, and that in an injection experiment RNAs might utilise either pathway, the distinction in fates being very subtle and subject to variation. We discuss these results in relation to their biological significance and the results of others
Investigations into Xpat, a novel gene expressed in the germ plasm and primordial germ cells of Xenopus laevis
No full textTo determine the expression pattern of XPAT (Xenopus primordial germ cell associated transcript) protein in Xenopus oocytes, XPAT-GFP fusion proteins were generated. When XPAT was amino-terminally tagged with GFP it became localised to the nuclei of stage VI Xenopus oocytes. However, when carboxy-terminally tagged with GFP, XPAT also translocated to the vegetal pole of stage VI oocytes. XPAT-GFP formed particles (1 to 2.5mm in diameter) which aggregated into large (10 to 50mm) granular structures at the vegetal pole. These particles looked exactly like those seen after in situ hybridisation to germ plasm RNAs. The granules of XPAT-GFP were larger than endogenous germ plasm granules seen in stage VI oocytes; they were more consistent with those observed in 2-cell embryos during germ plasm aggregation. Studies involving the use of the anticytoskeletal drugs colcemid, nocodazole and cytochalasin D and the microtubule stabilising agent taxol indicated that microtubular transport was important in the location of XPAT-GFP. Several attempts were made to raise antibodies to XPAT peptides, but at present the endogenous expression pattern of XPAT protein is unresolved.
To investigate possible domain structure of XPAT, one carboxy-terminal and three amino-terminal deletion variants of XPAT-GFP were constructed. An N-terminal deletion protein lacking the first 61 amino acids of XPAT was able to form small particles, but none of the deletion proteins exhibited vegetal localisation or formed large aggregates in Xenopus oocytes. The N-terminal deletion proteins all became predominantly localised to the nucleus; protein motif analysis revealed that XPAT contains a putative bipartite NLS in its carboxy-terminal region. The C-terminal deletion protein, which lacked the putative NLS, was evenly distributed throughout the nucleus and cytoplasm of Xenopus oocytes.
XPAT was shown to be able to bind to homopolymeric RNAs in vitro. When Xpat mRNA was depleted from stage VI Xenopus oocytes (by injection of an antisense oligo) levels of DEADSouth and XVLG1 mRNAs decreased substantially
Frontières épaisses
No full textLe 2 février 2010 A. Ariel de Vidas (MASCIPO), M. Fulbert et K. Chavarochette (ethnologie, ethnohistoire) "réflexion à partir de leur terrain sur le thème : « les effets d'une crise: quelle crise ? -quelle version de l'histoire et quelle frontière/espace se redéfinissentt à partir de cette crise ?
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