Rapport d\u27analyse ­ Enquête : Les données de la recherche à l\u27université ParisSaclay, panorama et perspectives

Cette enquête, proposée par l’ensemble du réseau des bibliothèques et centres de documentation et le Comité de pilotage de la Science Ouverte de l’Université Paris-Saclay en 2021, s’inscrit dans un contexte dynamique de Science Ouverte prônant l’obligation de publication des données de la recherche selon les principes FAIR (Facilement trouvable, Accessible, Interopérable, Réutilisable)

Differential roles of the Drosophila EMT-inducing transcription factors Snail and Serpent in driving primary tumour growth.

Several transcription factors have been identified that activate an epithelial-to-mesenchymal transition (EMT), which endows cells with the capacity to break through basement membranes and migrate away from their site of origin. A key program in development, in recent years it has been shown to be a crucial driver of tumour invasion and metastasis. However, several of these EMT-inducing transcription factors are often expressed long before the initiation of the invasion-metastasis cascade as well as in non-invasive tumours. Increasing evidence suggests that they may promote primary tumour growth, but their precise role in this process remains to be elucidated. To investigate this issue we have focused our studies on two Drosophila transcription factors, the classic EMT inducer Snail and the Drosophila orthologue of hGATAs4/6, Serpent, which drives an alternative mechanism of EMT; both Snail and GATA are specifically expressed in a number of human cancers, particularly at the invasive front and in metastasis. Thus, we recreated conditions of Snail and of Serpent high expression in the fly imaginal wing disc and analysed their effect. While either Snail or Serpent induced a profound loss of epithelial polarity and tissue organisation, Serpent but not Snail also induced an increase in the size of wing discs. Furthermore, the Serpent-induced tumour-like tissues were able to grow extensively when transplanted into the abdomen of adult hosts. We found the differences between Snail and Serpent to correlate with the genetic program they elicit; while activation of either results in an increase in the expression of Yorki target genes, Serpent additionally activates the Ras signalling pathway. These results provide insight into how transcription factors that induce EMT can also promote primary tumour growth, and how in some cases such as GATA factors a ‘multi hit’ effect may be achieved through the aberrant activation of just a single gene

Specification of leading and trailing cell features during collective migration in the Drosophila trachea

The role of tip and rear cells in collective migration is still a matter of debate and their differences at the cytoskeletal level are poorly understood. Here, we analysed these issues in the Drosophila trachea, an organ that develops from the collective migration of clusters of cells that respond to Branchless (Bnl), a fibroblast growth factor (FGF) homologue expressed in surrounding tissues. We track individual cells in the migratory cluster and characterise their features and unveil two prototypical types of cytoskeletal organisation that account for tip and rear cells respectively. Indeed, once the former are specified, they remain as such throughout migration. Furthermore, we show that FGF signalling in a single tip cell can trigger the migration of the cells in the branch. Finally, we found specific Rac activation at the tip cells and analysed how FGF-independent cell features, such as adhesion and motility, act on coupling the behaviour of trailing and tip cells. Thus, the combined effect of FGF promoting leading cell behaviour and the modulation of cell properties in a cluster can account for the wide range of migratory events driven by FGF. © 2014. Published by The Company of Biologists Ltd.This work has been supported by the Generalitat de Catalunya, the Spanish Ministerio de Ciencia e Innovacion and its Consolider-Ingenio 2010 program. G.L. was supported by Fondation pour la Recherche Médicale [grant number SPE20081214952]; the European Molecular Biology Organisation [grant number ALTF 978-2009] and Consejo Superior de Investigaciones CientíficasPeer Reviewe

L'enseignement de la langue à des «allophones»: l'expérience des collèges anglophones /

Tiré de l'écran-titre (visionné le 27 mars 2013)

Supracellular organisation in Drosophila trachea morphogenesis

Trabajo presentado en la 25th Annual French Drosophila Conference, celebrada en Lyon, Francia, del 17 al 20 de octubre de 2011Morphogenesis in general and organogenesis specifically are very complex events that involve global changes within cell populations. They have to be orchestrated at the level of their individual cell properties, but also require a supracellular upper level of organisation. How collective behaviour can be generated from individual cell properties is the question we want to address by studying the morphogenesis of the embryonic Drosophila tracheae. We have begun our analysis by characterising the dynamic cellular organisation during the formation of a specific branch. Our main focus has been to identify the differences between two cell types that behave distinctively during the formation of this branch, the leading cells (Lc) at the tip of the branch, and the trailing cells (Tc) behind. We have explored their specific organisation, in terms of shape, polarity,adhesion, and cytoskeleton organisation during the distinct steps of branch formation. This comparative analysis shows that the Lcs maintain a small apical membrane throughout the process and have distinct actin polymerisation properties. Moreover, the actin accumulation pattern highlights the supracellular organisation level during the branching events, something we are currently exploring. Through this work we hope to better understand the relationship between these interconnected and coordinated unicellular events, their function and the molecular mechanisms involved.Peer Reviewe

Ligand-binding and constitutive FGF receptors in single Drosophila tracheal cells. Implications for the role of FGF in collective migration

[Background] The migration of individual cells relies on their capacity to evaluate differences across their bodies and to move either toward or against a chemoattractant or a chemorepellent signal respectively. However, the direction of collective migration is believed to depend on the internal organization of the cell cluster while the role of the external signal is limited to single out some cells in the cluster, conferring them with motility properties.[Results] Here we analyzed the role of Fibroblast Growth Factor (FGF) signaling in collective migration in the Drosophila trachea. While ligand-binding FGF receptor (FGFR) activity in a single cell can drive migration of a tracheal cluster, we show that activity from a constitutively activated FGFR cannot—an observation that contrasts with previously analyzed cases.[Conclusions] Our results indicate that individual cells in the tracheal cluster can “read” differences in the distribution of FGFR activity and lead migration of the cluster accordingly. Thus, FGF can act as a chemoattractant rather than as a motogen in collective cell migration. This finding has many implications in both development and pathology.G.L. was supported by FRM, EMBO, and CSIC. This work has been supported by the Generalitat de Catalunya, the Spanish Ministerio de Ciencia e Innovacion, and its Consolider-Ingenio 2010 program.Peer Reviewe

The making of a fusion branch in the Drosophila trachea

Connection of epithelial tubes to generate a common network is a key step in the formation of tubular organs such as the tracheal respiratory and the vascular systems. However, it is not clear how these connecting tubes arise. Here we address this issue by studying the dorsal fusion branches in the Drosophila trachea, taking into account the morphology and contribution of each cell type on the basis of their individual labeling. Our results explain how a fusion branch forms and also illustrate the different nature of the two seamless tubes in the Drosophila trachea, generated by fusion and terminal cells respectively. © 2011 Elsevier Inc.L.G. was supported by the FRM, EMBO and CSIC. G.L was supported by the FRM and by the EMBO. This work has been supported by the Generalitat de Catalunya, the Spanish Ministerio de Ciencia e Innovacion and its Consolider-Ingenio 2010 program.Peer Reviewe

Cell migration in Drosophila morphogenesis

Trabajo presentado en la 25th European Drosophila Research Conference, celebrada en Londres, del 22 al 25 de septiembre de 2017Cell migration plays a fundamental role in development and homeostasis. This event is very often associated with static cells acquiring migratory capacity and becoming motile at very precise times and settings. This behaviour is one of the most characteristic examples of the epithelial cell plasticity. Not surprisingly, inappropriate migration is often associated with many pathological conditions. We are studying these phenomena of cell plasticity in the context of the whole organism taking advantage of the Drosophila model and I will present the results of our lab in cell plasticity in the morphogenesis of the Drosophila digestive and tracheal systemsN

Ségrégation et différenciation des cellules à l'origine des palpes maxillaires et des antennes de la tête adulte de drosophile

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF