Fig. 3

Strong id3 expression in type 3 progenitors and weak id4 expression in neural progenitors. A to L: id3 in situ hybridization (red) followed by PCNA (blue) and S100β (green) immunohistochemistry in the telencephalon. Id3 appears to be mainly and strongly expressed in the ventricular layer of the subpallium. E to H: high magnification views of the upper white box in D corresponding to the Dm region. A weak id3 expression is detected in non-proliferative (arrow) and proliferative (arrowhead) S100β-positive radial glial cells (type 1 and type 2 cells, respectively). I to L: high magnification views of the lower white box in D corresponding to the rostral migratory stream like region (RMS) region. The asterisks show a strong id3 expression in type 3 progenitors (S100β-negative and PCNA-positive) of the RMS. M to X: id4 in situ hybridization (red) followed by PCNA (blue) and S100β (green) immunohistochemistry in the telencephalon. id4 expression appears to be widely expressed in the parenchyma but not in the ventricular layer. Q to T: high magnification views of the upper white box in D corresponding to the Dm region. id4 transcripts are mainly absent from non-proliferative (arrow) and proliferative (arrowhead) S100β-positive radial glial cells (type 1 and type 2 cells, respectively). U to X: high magnification views of the lower white box in P corresponding to the RMS region. In the RMS, id4 expression is barely detected in type 3 progenitor (S100β-negative and PCNA-positive) as shown with asterisks. Scale bar: 15 µm (I to L); 20 µm (U to X); 35 µm (Q to T); 40 µm (E to H); 130 µm (M to P); 250 µm (A to D).