expressed AMPA-type glutamate receptors GluA1, A2, and A4, but lacked NMDA-type glutamate receptors 3 weeks after induction (Fig. 3A). Moreover, nearly all iN cells expressed vGlut2, and approximately 20% of iN cells expressed vGlut1. iN cells highly expressed GABAA-receptors but lacked the vesicular GABA-transporter vGAT or the GABA-synthetic enzyme glutamate decarboxylase (GAD). Ngn2 iN cells expressed all pan-neuronal markers tested, but lacked expression of markers for various glia cell types or for stem cells (Figs. 3A and S3B). These measurements show that Ngn2 iN cells are relatively homogeneous, and that they constitute excitatory neurons that express telencephalic markers suggestive of cortical layers 2/3.
