Asymmetric inheritance of radial glial fibers by cortical neurons

Recent studies demonstrated the neuronogenic role of radial glial cells (RG Cs) in the rodent. To reveal the fate of radial glial processes, we intensi vely monitored divisions of RGCs in Dil-labeled slices from the embryonic d ay 14 mouse cortex. During RGC division, each pia-connected fiber becomes t hin but is neither lost nor divided; it is inherited asymmetrically by one daughter cell. In divisions that produce a neuron and a progenitor, the neu ron inherits the pial fiber, also grows a thick ventricular process for sev eral hours, and is therefore indistinguishable from the progenitor RGC. The ventricular process in the radial glial-like neuron ("radial neuron") then collapses, leading to ascent of the neuron by using the "recycled" radial fiber.