Regulation of rodent myelin proteolipid protein gene expression

The regulation of rodent proteolipid protein (PLP) gene expression was studied during rat development and in cultured cells. Nuclear run-on assays demonstrate a strong transcriptional component associated with the developmental regulation of the PLP mRNA. Transcription rates of the PLP and MBP genes parallel their respective steady-state mRNA levels throughout rat brain development. In addition, a moderate 25-h half-life was measured for PLP mRNA in 37-day-old cultured oligodendrocytes, suggesting that regulation of PLP expression occurs predominantly at the transcriptional level. Finally, 5400 and 1400 bp of mouse PLP 5'-flanking sequence demonstrate transcriptional activity 13-fold and 5-fold above background, respectively, in hamster glial cells. Far upstream elements are clearly involved in transcription of the PLP gene. The 5400 bp sequence demonstrates no more activity than the 1400 bp in a mouse hepatoma cell line suggesting that elements involved in the glial cell-specific expression of PLP lie between 1400 and 5400 bp upstream of the gene.