FIG. 4.

Down-regulation of CRX-mediated transactivation by Phd and PhLOP1 in transiently cotransfected COS-7 or retinoblastoma Weri-Rb-1 cells. COS-7 (A) and Weri-Rb-1 cells (B) were cotransfected with 1 μg of the reporter construct pIRBP and expression plasmids for bCRX (0.4 μg) and/or Phd or PhLOP1 (0.4 μg). The promoterless pRL-null vector was cotransfected with the pcDNA3 vector as a control for basal luciferase activity of the cells, and its luciferase activity was set at 1 (left bar). pGL3-P control plasmid (0.2 μg) was added to each sample as an internal control for transfection efficiency. Total amounts of DNA were adjusted with the pcDNA3 vector. Values are means ± standard errors of results from three or four independent experiments performed in duplicate. (C and D) COS-7 cells were cotransfected with the indicated amount of each plasmid and with 0.2 μg of pGL3-P control plasmid. Total amounts of DNA were adjusted with the pcDNA3 vector. Values are means ± standard errors of the means of results from three independent experiments performed in duplicate.