show Abstracthide AbstractThe ChIP-seq and RNA-seq studies form part of a wider investigation into the role of bromodomain factor 5 in transcriptional regulation of the Leishmania genome. Cas9-driven gene deletions implicated BDF1-5 to be essential in promastigotes, whilst DiCre inducible gene deletion of the dual bromodomain factor BDF5 identified it to be essential for both promastigotes and amastigotes. ChIP-seq assessment of BDF5 genomic distribution identified it as enriched at transcriptional start sites. Using an optimised proximity proteomic and phosphoproteomic technique, XL-BioID, we defined the BDF5-proximal environment to be enriched for other bromodomain factors, histone acetyltransferase 2, proteins essential for transcriptional activity and RNA processing. Following inducible deletion of BDF5, transcriptional activity was disrupted for all pol II transcription units, leading to a global defect in gene expression. Our results indicate the requirement of Leishmania to interpret histone acetylation marks for normal levels of gene expression and thus cellular viability.