Genome-wide analysis of gene expression relationships in transcriptional regulatory networks

From merging a number of data sources, we created an extensive map of the transcriptional regulatory network in yeast, comprising 7419 interactions connecting 180 transcription factors (TFs) with their target genes. We integrated this network with gene-expression data, relating the expression profiles of TFs and target genes. We found that genes targeted by the same TF tend to be co-expressed, with the degree of co-expression increasing if genes share more than one TF. Moreover, shared targets of a TF tend to have similar cellular functions. In contrast, the expression relationships between the TFs and their targets are much more complicated, often exhibiting time-shifted or inverted behavior.