Uncharted Territory: Mapping Transcription Factor Binding in Human Tissues

The human genome contains approximately 1,600 types of transcription factors responsible for regulating gene activity across more than 400 tissue and cell types. Chromatin immunoprecipitation sequencing (ChIP-seq) is a key approach for mapping how these factors interact with DNA to control gene expression. However, practical limitations, such as the limited availability of suitable antibodies, have hindered efforts to comprehensively characterize transcription-factor binding, leaving many biologically important contexts uncharted. In this study, researchers systematically analyzed large-scale publicly available human ChIP-seq data to identify highly expressed transcription factor-tissue/cell type pairs whose activity remains unmeasured. They found that althoughblood cellshave been extensively studied far more than other tissues, over 80% of transcription factor-tissue/cell type combinations in organs such as the pancreas, muscle, and placenta has never been measured. This highlights significant gaps in current knowledge, suggesting that essential regulatory mechanisms may have been overlooked. The findings arepublishedin the journalBriefings in Functional Genomics.