Figure 2: NeuroD1 converts lineage-traced astrocytes into neuronal nuclei (NeuN)+ neurons. (A) tdTomato(tdT)-labeled cells in non-infected contralateral cortex (top panel) and AAV5 NeuroD1-infected cortex (bottom panel) in Aldh1l1-CreERT2 x Ai14 mice. Scale bar: 200 μm. (B) NeuroD1 expression detected in tdTomato+ cells in Aldh1l1-CreERT2 X Ai14 mice at early days of AAV infection (7 dpi, arrowheads). Scale bar: 20 μm. (C1) In contralateral cortex without viral injection (Box C1 in panel A), tdT-labeled cells were NeuN negative, as expected. (C2) In NeuroD1-infected cortex (Box C2 in panel A), some tdT-labeled cells were NeuN positive and showed clear neuronal morphology. Scale bar for C1 and C2: 20 μm. (D, E) Quantitative analysis revealed that NeuN and tdT double-positive cells increased significantly in the NeuroD1-infected group, compared to the contralateral control side. n = 5 for the control group, n = 3 for the NeuroD1-infected group. **P < 0.01, Student’s t-test. dpi: Day post injection.