| Cells of the oligodendrocyte lineage go through a complex sequence of division, migration and differentiation. In transgenic mice in which the first exon of myelin basic protein (MBP) has been replaced with the Lac Z reporter gene, Lac Z expression emerges adjacent to the putative source of the oligodendrocyte lineage, after PDGFaR-expressing progenitors have left the ventricular zone. This suggests transcriptional activity at the MBP locus begins in oligodendrocytes at the premyelinating stage of development. Low-level Lac Z expression is also observed in the presumptive grey matter from embryonic day 12 (E12).;In contrast, transgenic mice bearing Lac Z fused to various lengths of the MBP promoter suggest that, while capable of driving expression in oligodendrocytes, the MBP promoter is unexpectedly sensitive to deregulation from elements adjacent to its chromosomal integration site. Expression of one construct may identify transcription factors involved in establishing the oligodendrocyte lineage as early as E9. |
