Figure 8.

hnRNP-K is not necessary for MAG expression and internode formation during myelination. (A) OPCs were infected with lentivirus miR RNA against hnRNP-K or a nontargeting control miR RNA as indicated. These cells were added to cultures of DRG neurons and the formation of internode-like structures and MBP expression by the oligodendrocytes they generate was analyzed after costaining with MAG (green), MBP (red), and neurofilament (blue). Note that reduced expression of MBP is seen in cells expressing the hnRNP-K miR RNA but that the formation of internode-like structures is unaffected. This is quantified in the next three panels, with means ±SD from at least 10 pictures from two coverslips in three independent experiments shown. (B) Number of MAG+ cells/40x field. (C) Number of MAG+ cells that have initiated wrapping as shown by internode-like structures. Note that internode formation is not affected by the reduction in MBP expression. (D) Percentage of MAG+ cells that are also MBP+, showing the expected reduction. Statistical significance was tested by one-way ANOVA followed by a Tukey’s multiple comparison test. *, P < 0.05; **, P < 0.01; ***, P < 0.001.