Figure 4

YY1 is autoregulated through its own binding sites. To demonstrate autoregulation through YY1's internal binding sites, we have analyzed the transcriptional activity of the zebrafish YY1 promoter with/without the YY1 binding sites at the two different cellular level of YY1 protein. These different conditions were set up using a Tet-On induction system over-expressing exogenous YY1. Before the transfection, the cell line was incubated in the absence (A) and presence (B) of the inducer, Dox. During transfection, Dox was added (A) and removed (B) to make the YY1 protein levels higher and lower, respectively, that the control cell line. Two constructs, Control and All mut, were individually transfected into the two different inducible cell lines, #7 and #16, along with the internal control luciferase vector (pGL3 control) in order to normalize β-gal activity.