Proteomics analysis of the bromodomain protein IBD2 reveals mechanistic insights into H2A.Z (Hv1) dynamics in Tetrahymena
INO80 and SWR1 are evolutionarily related ATP-dependent chromatin remodeling complexes that regulate the chromatin occupancy of the histone variant H2A.Z, playing critical roles in transcriptional regulation, genome replication, and DNA repair. While INO80 and SWR1's H2A.Z-related functions are well characterized in budding yeast and metazoans, much less is known about their composition and conserved roles outside the Opisthokonts. Here, we report that in the ciliate protozoan Tetrahymena thermophila, a distinct bromodomain-containing protein, IBD2, functions as a component of a putative INO80 complex. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) demonstrates that IBD2 is enriched near transcription start sites and promoter regions. Notably, the IBD2 genomic binding profile strongly correlates with that of H2A.Z (Hv1), supporting its association with the INO80 complex. Overall design: Examination of ChIP DNA for Ibd2-FZZ cells (biological duplicates) during vegetative growth. Examination of RNA of Wild type cells (biological duplicates) and Ibd1 KO cells (biological triplicates) during vegetative growth