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Neurons in the developing rodent cortex are generated from radial glial cells that function as neural stem cells. These epithelial cells line the cerebral ventricles and generate intermediate progenitor cells that migrate into the subventricular zone (SVZ) and proliferate to increase neuronal number. The developing human SVZ has a massively expanded outer region (OSVZ) thought to contribute to cortical size and complexity. However, OSVZ progenitor cell types and their contribution to neurogenesis are not well understood. Here we show that large numbers of radial glia-like cells and intermediate progenitor cells populate the human OSVZ. We find that OSVZ radial glia-like cells have a long basal process but, surprisingly, are non-epithelial as they lack contact with the ventricular surface. Using real-time imaging and clonal analysis, we demonstrate that these cells can undergo proliferative divisions and self-renewing asymmetric divisions to generate neuronal progenitor cells that can proliferate further. We also show that inhibition of Notch signalling in OSVZ progenitor cells induces their neuronal differentiation. The establishment of non-ventricular radial glia-like cells may have been a critical evolutionary advance underlying increased cortical size and complexity in the human brain., One of the most marked evolutionary changes underlying the unique cognitive abilities of humans is the greatly enlarged cerebral cortex. This change must be reflected in differences in progenitor cell [...]

Zika virus (ZIKV) is a flavivirus transmitted via mosquitoes and sex to cause congenital neurodevelopmental defects, including microcephaly. Inherited forms of microcephaly (MCPH) are associated with disrupted centrosome organization. Similarly, we found that ZIKV infection disrupted centrosome organization. ZIKV infection disrupted the organization of centrosomal proteins including CEP63, a MCPH‐associated protein. The ZIKV nonstructural protein NS3 bound CEP63, and expression of NS3 was sufficient to alter centrosome architecture and CEP63 localization. Loss of CEP63 suppressed ZIKV‐induced centrosome disorganization, indicating that ZIKV requires CEP63 to disrupt centrosome organization. ZIKV infection or CEP63 loss decreased the centrosomal localization and stability of TANK‐binding kinase 1 (TBK1), a regulator of the innate immune response. ZIKV infection also increased the centrosomal accumulation of the CEP63 interactor DTX4, a ubiquitin ligase that degrades TBK1. Therefore, we propose that ZIKV disrupts CEP63 function to increase centrosomal DTX4 localization and destabilization of TBK1, thereby tempering the innate immune response. Synopsis: Brazilian Zika virus (ZIKV) infection disrupts centrosome organization and destabilizes TBK1, thereby dampening innate immune response activation. ZIKV protein NS3 localizes to the centrosome and redistributes the microcephaly‐associated protein CEP63 from the centrosome.Acentrosomal CEP63 recruits the ubiquitin ligase DTX4 leading to the degradation of TBK1, a regulator of innate immunity.TBK1 loss prevents the activation of the innate immune response in ZIKV‐infected cells. [ABSTRACT FROM AUTHOR]

Author(s): Laura A. B. Elias (corresponding author) [1, 2]; Doris D. Wang [1, 2]; Arnold R. Kriegstein (corresponding author) [2] During neocortical brain development, radial glia, which reside in the [...]

Real-time imaging of migrating neurons has changed our understanding of how newborn neurons reach their final positions in the developing cerebral cortex. The migratory routes and modes of migration are more diverse and complex than previously thought. The finding that cortical interneurons migrate to the cortex from origins in the ventral telencephalon has already markedly altered our view of cortical migration. More recent findings have demonstrated additional nuances in the migratory pattern and highlighted differences between subsets of interneurons. Moreover, radial migration of pyramidal neurons does not progress smoothly from ventricle to cortical plate, but is instead characterized by distinct migratory phases in which neurons change shape and direction of movement. Integrating these findings with the molecular machinery underlying migration will provide a more complete picture of how the cerebral cortex is assembled.

Author(s): Stephen C. Noctor [1]; Alexander C. Flint [1]; Tamily A. Weissman [2]; Ryan S. Dammerman [2]; Arnold R. Kriegstein (corresponding author) [1, 2, 3] The neocortex of the adult [...]

Radial glial cells, the stem cells of the cerebral cortex, extend a long basal fiber that ends in basal endfeet. A new study in PLOS Biology found that non-muscle myosins control basal endfoot integrity to regulate interneuron organization. Radial glial cells, the stem cells of the cerebral cortex, extend a long basal fiber that ends in basal endfeet. This Primer explores the implications of a new PLOS Biology study revealing that non-muscle myosins control basal endfoot integrity to regulate interneuron organization. [ABSTRACT FROM AUTHOR]