RoEduNet 2006

Short Abstract — Intergenic tandem repeats (TRs) containing transcription factor (TF) binding sites could serve as DNA decoys competitively binding TFs and affecting target gene expression. Using a yeast synthetic system, we demonstrate that repeated decoy sites tightly sequester a transcriptional activator and inhibit the promoter activation, creating a sigmoidal-like dose-response. This altered response can qualitatively change a network behavior by converting a transcriptional positive feedback response from graded to bimodal. Finally, we find that the TR’s binding affinity for TF becomes lower with increasing activator level, implying a possibility of anticooperative binding.