Connexin expression by radial glia-like cells is required for neurogenesis in the adult dentate gyrus

In the adult dentate gyrus, radial glia-like cells represent putative stem cells generating neurons and glial cells. Here, we combined patch-clamp recordings, biocytin filling, immunohistochemistry, single-cell transcript analysis, and mouse transgenics to test for connexin expression and gap junctional coupling of radial glia-like cells and its impact on neurogenesis. Radial glia-like cells were identified in mice expressing EGFP under control of the nestin and gfap promoters. We show that a majority of Radial glia-like cells are coupled and express Cx43. Neuronal precursors were not coupled. Mice lacking Cx30 and Cx43 in GFAP-positive cells displayed almost complete inhibition of proliferation and a significant decline in numbers of radial glia-like cells and granule neurons. Inducible virus-mediated ablation of connexins in the adult hippocampus also reduced neurogenesis. These findings strongly suggest the requirement of connexin expression by radial glia-like cells for intact neurogenesis in the adult brain and point to possible communication pathways of these cells.