Figure 4: Contribution of Sbno1 to transcriptional activation mediated by Yap/Tead and Notch/Rbpj.
(a) Transcriptional activities of δ-crystalline minimal promoter-luciferase with Tead binding sites (8xGT-IIc Tead reporter) were measured. Yap activated this Tead reporter (60.7-fold), and the activation was repressed by knocking down endogenous SBNO1 (SBNO1 siRNA) (26.0-fold). (b) Transcriptional activities of δ-crystalline minimal promoter-luciferase with Gal4-binding sites (Gal4-UAS) were measured. Gal4-SBNO1 alone stimulated transcription (68.6-fold), and this activation was further enhanced by Yap (1396.4-fold). GAL4-Tead4, which did not activate the reporter alone (0.25-fold), showed robust synergistic activation with Yap (8106.6-fold). (c) When 293 T cells were seeded at different cell densities (2 × 104, 5 × 104 and 1 × 105 cells/well in 24-well plates the synergistic activation by Gal4-SBNO1 and Yap was robust at the low cell density (3088.7-fold), but not at the high cell density (343.5-fold). (d) The TP1 Notch reporter (12x Rbpj binding sites-βglobin promoter-Luc) was activated by Notch1ΔE (35.2-fold), and this activation was repressed by SBNO1 siRNA (18.9-fold). (e,f) Activation of the 8xGT-IIc Tead reporter by Yap (e) and TP1 Notch reporter by NotchΔE (f) was reversed by the SBNO1-E437Q mutant in a dose-dependent manner. All data are presented as means ± SD. **p < 0.01 versus relevant control.
