A comprehensive Schizosaccharomyces pombe atlas of physical transcription factor interactions with proteins and chromatin [ChIPseq]
Transcription factors (TFs) are key regulators of gene expression, yet many of their targets and modes of action remain unknown. In Schizosaccharomyces pombe, one-third of TFs are solely homology-predicted, with few experimentally validated. We created a comprehensive library of 89 endogenously tagged S. pombe TFs, mapping their protein and chromatin interactions using immunoprecipitation mass-spectrometry and chromatin immunoprecipitation sequencing. Our study identified protein interactors for half the TFs, with over a quarter potentially forming stable complexes. We discovered DNA binding sites for most TFs across 2,027 unique genomic regions, revealing motifs for 38 TFs and uncovering a complex regulatory network of extensive TF cross- and autoregulation. Characterization of the largest TF family revealed conserved DNA sequence preferences but diverse binding patterns, and identified a repressive heterodimer, Ntu1/Ntu2, linked to perinuclear gene localization. Our TFexplorer webtool makes all data interactively accessible, offering new insights into TF interactions and regulatory mechanisms with broad biological relevance. Overall design: Chromatin immunoprecipitation DNA-sequencing (ChIP-seq) for endogenously tagged transcription factors in vegetatively growing Schizosaccharomyces pombe cells.