Systematic expansion of the regulatory network(Contd Three different network expansion scenarios were investigated Only chIP-chip and motif data for the 55 TFs already included in the model were used. And the direction of the expression change for each target gene would be correctly explained as a combination of the regulatory interactions along the path when each tf was considered to be either a repressor or activator depending on its known activity The same set of ChlP-chip and motif data sets was used, but the assumption that specific transcription factors can only act as activators or repressors was relaxed ChIP-chip and motif data for all 203 TFs studied in harbison et al were included, again allowing each tF to act either as a repressor or activator.Systematic expansion of the regulatory network (Cont’d) • Three different network expansion scenarios were investigated. – Only ChIP-chip and motif data for the 55 TFs already included in the model were used. And the direction of the expression change for each target gene would be correctly explained as a combination of the regulatory interactions along the path when each TF was considered to be either a repressor or activator depending on its known activity. – The same set of ChIP-chip and motif data sets was used, but the assumption that specific transcription factors can only act as activators or repressors was relaxed. – ChIP-chip and motif data for all 203 TFs studied in Harbison et al. were included , again allowing each TF to act either as a repressor or activator