Distinct groups of transcription factors (TFs) assemble at tissue-specific cis-regulatory sites,
implying that different TF combinations may control different genes and cellular functions.
Within such combinations, TFs that specify or maintain a lineage and are therefore
considered master regulators may play a key role. Gene enhancers often attract these tissue-
restricted TFs, as well as TFs that are expressed more broadly. However, the contributions of
the individual TFs to combinatorial regulatory activity have not been examined critically in …