The mechanisms and signals that limit the proliferation of neural stem cells during early development, ensuring that the nervous system contains the adequate number of neurons and glia in adults, is a fundamental question in developmental biology that remains poorly understood. In an article published in Development, the team of Cédric Maurange has identified in Drosophila Melanogaster two different types of signals whose action converges towards a single gene, chinmo, which must be silenced to allow termination of neural stem cell divisions and their differentiation .

Depending on the type of stem cells and the region of the brain, chinmo is switched off either by a post-transcriptional mechanism involving an intrinsic cellular clock, or at the transcriptional level by an extrinsic signal, a steroid hormone, which coordinates the differentiation of neural stem cells with the maturation of other tissues in the body. This study illustrates the variety of mechanisms that limit the proliferation of different types of neural stem cells while acting on the regulation of a single “master” gene. This work paves the way towards a better understanding of developmental pathologies caused by the deregulation of neural stem cell proliferation (for example: microcephaly, pediatric neural cancers …)

Artwork by Caroline Dillard from a confocal image of a Drosophila larval brain. In yellow and magenta are the different types of neural stem cells found in the developing brain. Neurons are represent ed in blue. Dividing cells are in white.

Artwork by Caroline Dillard from a confocal image of a Drosophila larval brain. In yellow and magenta are the different types of neural stem cells found in the developing brain. Neurons are represent ed in blue. Dividing cells are in white.

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