Figure 2. SMN inhibits FGF-223 activation of Nurr1-dependent transcription.
In this reporter-gene assay, the effects of FGF-223, Nurr1 and SMN on transcription driven from the Nurr1 monomer binding responsive element (NBRE) were assessed by transfection of neuroblastoma cells NB. For this purpose, expression vectors for each protein and the NBRE-Luc reporter were used. Empty vector pcDNA3.1 was employed as a FGF-2 expression negative control and pβ-gal as a negative control for SMN constructs. Full-length-SMN (SMN1-294) inhibits transcriptional activation mediated by FGF-223, whereas coexpression of the SMN mutant protein SMN235-294 (without the N-terminal FGF-223-binding sequence and comprising amino acid residues 235-294) did not exhibit an inhibitory effect. Data represent the mean ± SEM of the ratio of firefly to Renilla luciferase activity (Fluc/Rluc) for n = 3 experiments, each performed in quadruplicate. Results were analyzed using one-way ANOVA followed by Tukeýs posthoc test (means ± SEM; ***, p<0.001; *, p<0.05; compared with pcDNA3.1/pNurr1.