The generation of a correctly-sized cerebral cortex with all-embracing neuronal and glial cell-type diversity critically depends on faithful radial glial progenitor (RGP) cell proliferation/differentiation programs. Temporal RGP lineage progression is regulated by Polycomb Repressive Complex 2 (PRC2) and loss of PRC2 activity results in severe neurogenesis defects and microcephaly. How PRC2-dependent gene expression instructs RGP lineage progression is unknown. Here we utilize Mosaic Analysis with Double Markers (MADM)-based single cell technology and demonstrate that PRC2 is not cell-autonomously required in neurogenic RGPs but rather acts at the global tissue-wide level. Conversely, cortical astrocyte production and maturation is cell-autonomously controlled by PRC2-dependent transcriptional regulation. We thus reveal highly distinct and sequential PRC2 functions in RGP lineage progression that are dependent on complex interplays between intrinsic and tissue-wide properties. In a broader context our results imply a critical role for the genetic and cellular niche environment in neural stem cell behavior.
We thank A. Heger (IST Austria Preclinical Facility), A. Sommer and C. Czepe (VBCF GmbH, NGS Unit) and S. Gharagozlou for technical support. This research was supported by the Scientific Service Units (SSU) of IST Austria through resources provided by the Imaging & Optics Facility (IOF), Lab Support Facility (LSF), and Preclinical Facility (PCF). N.A. received funding from the FWF Firnberg-Programm (T 1031). The work was supported by IST institutional funds and by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement 725780 LinPro) to S.H.