Studying maintenance and specification mechanisms in stem and progenitors cells in Xenopus retina
type: Distribution
access URL: https://theses.hal.science/tel-00980574
format: HTML
issued: 2026-05-05T14:09:16.540317
modified: 2026-05-05T14:09:16.518542

test_moissonnage_selune
type: Agent

Studying maintenance and specification mechanisms in stem and progenitors cells in Xenopus retina
type: Dataset
contact point: Organization
  fn: CCSD
keyword: infoeu-reposemanticsdoctoralthesis
keyword: gabaergic-neurons
keyword: neural-stem-cells
keyword: neurones-gabaergiques
keyword: cell-fate-choice
keyword: retinal-cell-subtypes
keyword: xenopus
keyword: retine
keyword: retina
keyword: sous-types-retiniens
keyword: sdvsalife-sciences-q-bioagricultural-sciences
keyword: choix-du-destin-cellulaire
keyword: cellules-souches-neurales
keyword: theses
keyword: voies-de-signalisation-wnt-et-hh
keyword: wnt-and-hh-signaling-pathways
keyword: xenope
landing page: https://theses.hal.science/tel-00980574
description: My thesis research work aimed to better understand the molecular mechanisms underlying proliferation and specification of retinal progenitors in Xenopus through three main projects. As the mechanisms governing specification of retinal progenitors towards the different neuronal subtypes are still poorly understood, I focused my work on the role of Ascl1, a bHLH transcription factor, in cell-subtype determination during retinogenesis. Using in vivo gain- and loss-of-function experiments, I have investigated Ascl1’s epistatic relationships with other bHLH factors and identified its transcriptional targets. My results indicate that Ascl1 (i) is implicated in the genesis of retinal GABAergic neurons (ii) is epistatic to glutamatergic factors such as Neurog2, NeuroD1 and Atoh7 (iii) that its basic DNA-biding domain is sufficient for its GABAergic-inducing activity (iv) and that this activity involves a direct regulation of the Ptf1a transcription factor. The correct order of neural cell types and subtypes formation is tightly coordinated with the timing of cell-cycle exit of retinal progenitors. Ongoing work in the laboratory, to which I have contributed, was therefore investigating the role of signaling pathways controlling retinal precursor proliferation in this process. Using in vivo genetic and pharmacological tools, we have shown that an antagonistic cross-regulation between Wnt and Hedgehog signaling governs stem cell and progenitor proliferation in post-embryonic retina. Preliminary data shows that Wnt and Hedgehog have opposite effects on both cell cycle exit and kinetics and may therefore regulate the proliferation/differentiation balance in the post-embryonic retina. Lastly, in order to broaden our knowledge on the transcriptional and signaling networks which govern proliferation and cell fate determination in the retina, I have participated in a large scale screen by in situ hybridization aiming to identify new molecular markers of different retinal cell popula…
identifier: NNT: 2012PA11T101
issued: 2026-05-05T14:09:16.538441
language: fr
modified: 2026-05-05T14:09:16.538445