Figure 7.

The hnRNPs expression in primary OLs and Oli-neu cells. (A) Representative RT-PCR products of the endogenous PLP and DM20 transcripts in RNA isolated from OPC and OLs differentiated for 72 h. The bar graph represents the mean ± SD (n = 3). (B) Representative Western blot of nuclear extracts prepared from OPC and OLs differentiated for 72 h and probed with antibodies specific for hnRNPA1, H, F and L (see Materials and Methods section). CNPase expression was assessed in cytoplasmic extracts. Tubulin is a control for loading accuracy. The data were reproduced in five separate primary OLs preparations. Bands were quantified by densitometry and the value was corrected by the internal control tubulin. The bar graph represents the percent expression ± SD of each protein in OLs nuclear extracts relative to the level detected in OPC nuclear extracts, which is set at 100 (n = 5). Reduction of H (P = 0.006), F (P = 0.003) and A1 (P = 0.02) in differentiated OLs versus OPC were all significant. (C) Representative Western blot of nuclear extracts prepared from undifferentiated Oli-neu cells (growth) and differentiated for 3, 7 and 10 days and probed with antibodies specific for hnRNPA1, H, F and L. Tubulin is control for loading accuracy. The data were reproduced in three separate experiments. Bands were quantified by densitometry and the values were corrected by the internal control tubulin. CNPase expression was assessed in cytoplasmic extracts. The bar graph represents the percent expression ± SD of each protein in the Oli-neu nuclear extracts relative to the level detected in undifferentiated cells, which is set at 100 (n = 3). The reduction of F and A1 expression in differentiated Oli-neu cells was significant at 7 and 10 days versus undifferentiated Oli-neu cells (P = 0.0017 for F and P = 0.001 for A1). The decrease of H in differentiated Oli-neu cells versus undifferentiated Oli-neu cells did not reach statistical significance. Levels of hnRNPL did not change.