Peroxisome proliferator-activated receptors (alpha, delta and gamma) are ligand-activated transcription factors that are involved in multiple cellular responses. The PPARdelta subtype is the least understood of all PPAR subtypes. PPARdelta is activated by unsaturated fatty acids, PGI2, and by synthetic ligands. PPARdelta-regulated genes have not been identified and the factors that control PPARdelta expression are not known. The gene that encodes the mouse PPARdelta gene is contained in >30 kb DNA sequence and organized in eight exons, six of which encode the PPARdelta receptor. A PPARdelta-luciferase reporter containing 694 bp 5' upstream regulatory and 127 bp untranslated was introduced to primary brain cultures to begin a characterization of the DNA sequences that mediate transcriptional regulation of PPARdelta. PPARdelta-luciferase expression was 10 times higher in oligodendrocyte-containing mature cultures than in immature cultures, indicating that PPARdelta may play a role during oligodendrocyte migration, proliferation, and/or maturation. (C) 2002 Elsevier Science.