Figure 4.

PLZF interferes with the transcriptional activity of RARα and of ERα, GR and VDR. A) Transcriptional activation of RARα is decreased upon overexpression of PLZF 3ZF or of full length PLZF. HeLa cells were transiently transfected with the p(GRARE)tkLuc reporter gene, the pSG5-RARα and the pSG5-RXGR expression vectors together with increasing amounts of pCMV-PLZF 3ZF or pSG5-PLZF expression vectors as indicated. Cells were treated with 1 μM atRA and luciferase activity was assayed 16 h later as described under "Experimental Procedures". Results are expressed as the mean +/- S.D. of at least three individual experiments, with the basal level of luciferase activity arbitrarily set to 1. B) PLZF inhibits the transcriptional activity of ERα, GR and VDR. HeLa cells were transiently transfected with the luciferase reporter genes p(ERE)3tkLuc, pVDREtkLuc or pCF3tkLuc and the pSG5-ERα, pSG5-VDR and pSG5-RXR or pRSV-GR expression vectors respectively. Cells were treated with 1 μM estradiol (E2), 0.1 μM Dexamethasone (Dex), or 1 μM vitamin D3 (Vit D3) respectively. Luciferase activity was assayed 16 h later.