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. Author manuscript; available in PMC: 2009 Jun 15.
Published in final edited form as: Biochem Biophys Res Commun. 2007 Dec 4;367(2):235–241. doi: 10.1016/j.bbrc.2007.11.151

Figure 2. Twist repression of E-cadherin promoter.

Figure 2

A, Dose dependent repression of E-cadherin promoter. Determination of the degree of suppression of the full-length E-cadherin promoter activity in the presence of increasing amounts of Twist plasmid in transient co-transfection assays. The Y103X mutant Twist construct (Mut) was used to test for specificity of repression. B, Upper panel shows a schematic of the E-cadherin promoter with E boxes shown as hollow triangles. Deletion constructs are indicated at 5′ end with E1–E7. Twist represses E-cadherin transcriptionally. Each of the 6 E-cadherin promoter reporter constructs was repressed 1.2 to 2 fold by Twist. The largest significant repression was seen in construct E4, indicating the importance of the proximal region in E-cadherin regulation by Twist. Statistical significance (P<0.05) is indicated by asterisks. C, Full length Twist is essential for E-cadherin repression. Upper panel shows E-cadherin E4 construct with E-box mutants indicated by M1, M2, and M3. Twist repression was statistically significant only in M1 construct indicating its lack of function in mediating the repression. This indicates that E-box 2 and 3 may play an important role in the down-regulation of E-cadherin by Twist. D, Upper panel shows Twist deletion mutants. Mutations are indicated with amino acids changed to stop codons. Lower panel shows mutant Twist constructs were unable to repress E-cadherin promoter significantly indicating that regions other than the basic helix loop helix domain play a role in the repression of E-cadherin.