Fig. 1
From: Shaking up the silence: consequences of HMGN1 antagonizing PRC2 in the Down syndrome brain
Schematic illustrating the proposed changes in neurogenesis and gliogenesis found in the DS brain. During neurodevelopment, neural progenitor cells, such as radial glial cells, generate neurons that migrate to the cortical plate and populate deep and superficial layers of the neocortex. Neurogenesis then is followed by gliogenesis, which results in the generation of glial cells, such as astrocytes and oligodendrocytes, that subsequently differentiate and mature. A premature shift from neurogenesis to gliogenesis is implicated in DS, with the potential manifestation of impaired neurogenesis, hypocellularity, an increase in the number of astrocytes, and a decrease in the number of mature oligodendrocytes. This precocious gliogenic switch can be attributed to a dosage effect of the triplicated genes (listed in the figure) resulting in a disruption of multiple signaling pathways implicated, shown in the figure. The dysregulation of these pathways can also be a result of the diminished activity of PRC2 due to increased levels of HMGN1 in DS. Created with BioRender.com