Figure 8.
Sox17 loss-of-function reveals a role in cell cycle exit and differentiation. Purified OPCs were cultured in the presence of PDGF (10 ng/ml) and transfected with Sox 17 siRNAs. A, Representative Western blot of Sox 17 protein levels shows a 60 and 80% reduction in Sox 17 expression at 24 and 48 h after transfection in PDGF, respectively. Numbers indicate hours after transfection. m, Mock transfected with scrambled sequence; s, Sox17 siRNA transfected. B, Downregulation of Sox17 expression induces an increase in OPC proliferation, as measured by anti-Ki67 and anti-BrdU staining (3 d after transfection). Cells were incubated with BrdU (20 μm) for 1.5 h before staining. Values represent percentage of total cells, as determined by DAPI counterstaining. Results are expressed as mean ± SEM of three to four experiments with a total number of cells counted ranging between 1475 and 2174 for each antibody. *p ≤ 0.005 (compared with mock-transfected cells), Student's t test. C, Downregulation of Sox 17 expression prevents OPC lineage progression, as determined by A2B5 and O4 (3 d after transfection) and O1 immunostaining (5 d after transfection). Values represent percentage of total cells, as determined by DAPI counterstaining. Results are expressed as mean ± SEM of three to four experiments with total numbers of cells counted ranging between 1381 and 1630 for each antibody. *p < 0.01 and **p ≤ 0.005 (compared with mock-transfected cells), Student's t test.