Fig. 4

Hemin inhibits transcription initiation at hemin-bound promoters. A UCSC genome browser tracks of Pol II ChIP-Rx, qPRO-seq, and TFIIB ChIP-Rx signals at the NPM1 locus in HEK293T cells. B,C Heatmap (B) and metaplot (C) analyses of Pol II ChIP-Rx signals at hemin-bound promoters demonstrate that hemin impeded Pol II occupancy at hemin-bound promoters. D Metaplot of strand-specific qPRO-seq signals at hemin-bound promoters. E, F Heatmap (E) and metaplot (F) analyses of TFIIB ChIP-Rx signals at hemin-bound promoters illustrate that hemin treatment impaired general transcription factor TFIIB occupancy at promoters. G–I Luciferase reporter assay of G4-containing promoters showed that hemin (G), ALA (H), and PpIX (I) treatments reduced luciferase reporter gene expression