TBLR1-RARα functions as a transcriptional activator. CV-1 (A) or HEK293 (B) cells were transfected with RARE Cignal reporter and expression plasmids containing vehicle, PML-RARα, RARα, and TBLR1-RARα, respectively. The transfected cells were then incubated with different dosages of ATRA or ethanol solvent for 48 hours and harvested for luciferase assay. TBLR1-RARα could increase the transcriptional activity of reporter gene. When treated with ATRA, TBLR1-RARα exhibited an ATRA-induced transcriptional activation in a concentration-dependent manner. The transcriptional capability of TBLR1-RARα was lower than that of wild-type RARα. Renilla luciferase activity was normalized to firefly luciferase activity. Ratios were normalized against the cells transfected with control plasmids. Bars represent mean values ± SD corresponding to at least 3 independent experiments executed in triplicate. Statistical significance was determined with the Student t test. **P < .01.