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. Author manuscript; available in PMC: 2009 Nov 1.
Published in final edited form as: Cancer Res. 2008 Nov 1;68(21):8852–8860. doi: 10.1158/0008-5472.CAN-08-0517

Fig. 2. Notch3 induces Pbx1 expression through promoter activation.

Fig. 2

A. Left Panel: Examples of the conserved CSL binding site in Notch-regulated genes in human. Consensus CSL binding sequence is bolded. The consensus CSL binding site is located at −304 to −292 at Pbx1 promoter. Right Panel: Pbx1 promoter assay shows increased reporter activity in cells transfected with the wild-type Pbx1 promoter construct (pGL3-Pbx1) as compared to cells transfected with vector only control (pGL3). In pGL3-Pbx1 transfected groups, cells co-transduced with both CSL and NICD3 retroviruses demonstrate the highest promoter activity. Cells transduced with vector only virus and pGL3-Pbx1 also showed above background luciferase activity, likely due to the endogenous background expression of CSL and Notch in OSE. In contrast, cells transfected with the mutant Pbx1 promoter construct (pGL3-Pbx1 mut) containing the mutant CSL binding site demonstrate a significantly lower luciferase activity as compared to that of wild-type Pbx1 promoter.

B. The pGL3-Pbx1 promoter construct was transfected into 3 cancer cell lines overexpressing Notch3. Pbx1 promoter activity was high in each of these transfected lines, but was significantly reduced by either GSI or Notch3 siRNA.