Sensitivity of virally-driven luciferase reporter plasmids to members of the steroid/thyroid/retinoid family of nuclear receptors

During a series of transfection experiments, the pRSV-luc plasmid used as a n internal control was found to be sensitive to co-transfection with expres sion vectors for several members of the steroid/thyroid/retinoid superfamil y of nuclear receptors, Therefore, a survey of the effect of these expressi on vectors on the activity of four reporter plasmids was conducted. In CV-1 cells, the activity of pRSV-luc, which contains the P. pyralis luciferase gene, was repressed by co-transfection of PPAR alpha and ARP-1 and was acti vated by COUP-TFI. Expression of pSV40-luc, containing the same luciferase gene, was repressed by PPARa and HNF-4 and activated by both COUP-TFI and A RP-1. All four of these expression vectors reduced the expression of the pR L-TK plasmid, which contains the luciferase gene from Renilla reniformis. R XR expression vectors had no effect on luciferase activity in CV-I cells bu t induced luciferase activity in H4IIEC3 hepatoma cells. This activation wa s blocked by the addition of ligand, 9-cis retinoic acid. pSV2-CAT, which c ontains the chloramphenicol acetyltransferase gene, was insensitive to all receptor expression vectors tested. Both the P. pyralis and R. reniformis l uciferase genes appear to contain sequences that render them responsive to steroid/thyroid/retinoid nuclear receptors. (C) 1999 Elsevier Science Ltd. All rights reserved.