Plp Gene Regulation in the Developing Murine Optic Nerve: Correlation with Oligodendroglial Process Alignment along the Axons

The factors regulating the expression and splicing of the major myelin gene, proteolipid protein (Plp), are unclear. The gene encodes two splice variants, Plp and Dm20. During active myelination, transcription of the Plp gene is markedly upregulated and the splice variant ratio becomes Plp-mRNA dominant. We hypothesised that these aspects of Plp gene regulation are linked to overt axonal contact. Using the developing optic nerve of mice, we demonstrate that alignment of oligodendroglial processes with the axon correlates with both the expression of Plp-mRNA and the transcriptional upregulation of the gene. We test the above hypothesis more extensively in a subsequent study.