Fig. 2: Characterization of cultured plexin-B3 + aOPCs.

a Plexin-B3 levels in cultured aOPCs (20 μg/lane). The abbreviations are the same as used in Fig. 1e). b Immunocytochemical analysis of aOPCs cultured in medium containing 0 or 20 ng/ml FGF2 for 5 days. Arrows indicate weakly NG2⁺ plexin-B3⁺ aOPCs. Scale bar: 20 μm. c Quantitative measurements of the intensities of plexin-B3 and NG2 immunoreactive areas of aOPCs cultured in medium containing 0 ng/ml FGF2 for 5 days. An example of a region of interest for a single cell is shown in the left panels of Fig. 3f. Note that plexin-B3⁺ aOPCs were generally NG2-negative and vice versa. Mean intensity: the integrated total value of signal intensities adjusted by single cell area. n = 172. d Effects of FGF2 on the levels of plexin-B3, NG2, PDGFRα and actin (20 μg/lane). For quantification, see Supplementary Fig. 4A. e BrdU incorporation in plexin-B3⁺ aOPCs. Scale bar: 20 μm. f Effects of treatment with the FGF inhibitor PD173074 (0, 50, or 500 nM in the presence of 20 ng/ml FGF2 for 24 h; Merck, Darmstadt, Germany), on the levels of plexin-B3. For quantification, see Supplementary Fig. 4B. g Effect of FGF2 withdrawal on the proportions of olig2⁺ cells. White arrows indicate dead cells that were strongly TO-PRO-3 positive. More than 99% of living cells were olig2⁺ under both conditions (see also Supplementary Table 2). h Effect of FGF2 withdrawal on MBP levels. FGF2 withdrawal for 5 days was not enough to increase MBP protein expression, although mRNA levels increased approximately 10-fold (Supplementary Fig. 4D & Data 5). E.I. enhanced image.