RAT PPAR-DELTA CONTAINS A CGG TRIPLET REPEAT AND IS PROMINENTLY EXPRESSED IN THE THALAMIC NUCLEI

We have isolated a new rat sequence containing motifs of a nuclear hor mone receptor from a brain cDNA library. The deduced amino acid sequen ce encoded by the cDNA clone showed a strong homology to the human NUC I and the mouse peroxisome proliferator activated receptor delta (PPAR delta). We therefore refer to this new clone as rat PPAR delta (rPPAR delta). The new feature of rPPAR delta is a 14 CGG triplet repeat on the 5' untranslated region, not previously reported in either NUCI or mPPAR delta. We found that rPPAR delta was expressed as a 3.5-kb trans cript which showed a wide distribution in adult rat tissues. Abundant expression was detected in brain, heart, skeletal muscle, kidney and l ung. Weaker expression was noted in the liver, spleen and testis. To d etermine the specific brain localization of rPPAR delta we performed i n situ hybridization analysis. Prominent expression was observed in th e thalamus, particularly in the posterior part of the ventral medial n ucleus, a site responsive to pain and cold stress. These results raise the possibility that PPAR delta might play a role in modulating respo nse to thermal and pain sensations.