FIG 2.
G144 cells express stage-specific oligodendrocyte mRNAs during in vitro differentiation. qRT-PCR analysis of oligodendrocyte lineage markers following 7 days of growth factor withdrawal revealed reduced expression of the OPC markers Neu1 and CSPG4 (NG2) compared with undifferentiated controls. (Neu1 makes a significant contribution to B-series ganglioside degradation in the brain [103], while NG2 is characteristically used to identify OPCs [reference 104 and references therein]). This reduction is accompanied by an increase in expression of the OG-associated Mal, Foxo4, MBP, and Foxo1 genes. As described by Goldman and Kuypers (28), the OG mRNAs were subdivided into those associated with premyelinating oligodendrocytes and myelinating oligodendrocytes. (Mal is predominantly localized in compact myelin [105], while Foxo4 is a transcription factor that is involved in growth and differentiation [106].) MBP, which is expressed in the nuclei of G144 cells, maintains the correct structure of myelin (107, 108), while the transcription factor Foxo1 has multiple roles, including the promotion of oligodendrocyte regeneration (109) and the regulation of apoptosis (reviewed in reference 110). The y axis presents the log2-fold change between the ΔCT values for the mRNAs collected from the undifferentiated and differentiated samples. Means (n = 3) are reported, and the error bars indicate standard deviations from the mean. The asterisks indicate significant differences between the undifferentiated and differentiated cells (P < 0.05).