Figure 7.

Schwann cells that lack laminin γ1 are present in nerves but do not differentiate. Sections of sciatic nerve from P28 d mutant mice were stained for S-100 (A and G), laminin γ1 (B and H), Krox-20 (C), and MBP (I). The images in A–C are merged in D. After photography, the sections were counterstained with DAPI, which is much stronger than the previous laminin staining using the same fluorescence dye, and therefore only showed DAPI staining (E). The DAPI-stained images were merged with S-100 (A) and Krox-20 (C) stained images and shown in F. The staining showed an S-100–positive Schwann cell (A, arrow) that did not express laminin γ1 (B, arrow) and did not show nuclei Krox-20 staining (C–F, arrow). An S-100–positive Schwann cell with its nuclei shown on this section (A and E, arrowheads) did express laminin γ1 (B, arrowhead) and showed nuclear Krox-20 staining (C, D, and F, arrowhead). The nuclei of the rest of the Schwann cells not indicated in A were not on this section. The correlation of laminin γ1 expression and MBP synthesis was also compared. An S-100–positive Schwann cell (G, arrow) did not express laminin γ1 (H, arrow) and did not produce MBP (I and J, arrow), whereas the rest of the S-100–positive Schwann cells (G, arrowhead) expressed laminin γ1 and produced MBP (H–J, arrowhead). Bars, 5 μm.