Biology subjects

Jolicoeur, C.

Publications and source records attributed to Jolicoeur, C..

3 recordsLinked to original sources

bioRxiv2022

Pou3f1 orchestrates a gene regulatory network controlling contralateral retinogeniculate projections

The balance of contralateral and ipsilateral retinogeniculate projections is critical for the establishment of binocular vision, but the transcriptional programs regulating this process remain ill-defined. In this study, we show that the Pou class homeobox protein POU3F1 is selectively expressed in developing mouse contralateral retinal ganglion cells (cRGCs). Inactivation of Pou3f1 increases the number of ipsilateral RGCs produced, leading to abnormal ipsilateral to contralateral projection ratio at the optic chiasm, whereas expression of Pou3f1 in retinal progenitors increases the production of cRGCs. Using Cut&Run and RNA sequencing in wildtype and Pou3f1 mouse knockout retinas, we demonstrate that Pou3f1 is necessary for the establishment of a cRGC gene regulatory network through activation and repression of several known contralateral and ipsilateral determinants, respectively. Finally, we report that POU3F1 is sufficient to induce production of RGC-like cells sending projections to the optic nerve, even in late-stage retinal progenitors not normally competent to generate RGCs. This work uncovers POU3F1 as a master regulator of the cRGC transcriptional program and opens new possibilities for optic nerve regenerative therapies.

developmental biology↗

bioRxiv2021

Numb reduces Tau levels and prevents neurodegeneration in mouse models of tauopathy in an isoform-specific manner

Accumulation of the microtubule-associated protein Tau is linked to neuronal cell death in tauopathies, but how exactly intraneuronal Tau levels are regulated in health and disease remains unclear. Here we identify the trafficking adaptor protein Numb as an essential regulator of Tau homeostasis. Conditional inactivation of Numb in retinal ganglion cells (RGCs) increases monomeric and oligomeric Tau levels, leading to axonal blebbing followed by neuronal cell loss in aged mice. Moreover, in a mouse model of tauopathy, inactivation of Numb in RGCs and spinal motoneurons accelerates neurodegeneration, and leads to precocious hindlimb paralysis. Conversely, overexpression of the long isoform of Numb (Numb-72), but not other isoforms, decreases intracellular Tau levels by promoting the extracellular release of monomeric Tau, and AAV-mediated delivery of Numb-72 in RGCs in vivo prevents neurodegeneration in two different mouse models of tauopathy. Taken together, these results uncover Numb as a modulator of intracellular Tau levels and identify Numb-72 as a novel therapeutic factor for tauopathies.

neuroscience↗

bioRxiv2020

A Casz1 - NuRD complex regulates temporal identity transitions in neural progenitors

Neural progenitor cells alter their output over developmental time to generate different types of neurons and glia in the correct sequences and proportions. A number of temporal identity factors that control transitions in progenitor competence have been identified, but the molecular mechanisms underlying their function remain unclear. Here, we asked how the transcription factor Casz1, the mammalian orthologue of Drosophila castor, regulates competence during retinal neurogenesis. We show that Casz1 is required to control the transition between neurogenesis and gliogenesis. Using BioID proteomics, we reveal that Casz1 interacts with the nucleosome remodeling and deacetylase (NuRD) complex in retinal cells. Finally, we show that both the NuRD and the polycomb repressor complexes are required for Casz1 to promote the rod fate and suppress gliogenesis. As other temporal identity factors have been found to interact with the NuRD complex in other contexts, we propose that these factors might act through a common biochemical process to regulate neurogenesis.

developmental biology↗