Task: Named Entity Recognition
Input (English):  Transient transfection assays indicated that the ( - 4551 ) UCP1 - CAT construct , containing the 5 ' - regulatory region of the rat ucp - 1 gene , was activated by PPARalpha co - transfection in a dose - dependent manner and this activation was potentiated by Wy 14 , 643 and retinoid X receptor alpha .
Output (English): retinoid X receptor