A combinatorial approach to uncover a novel Integrator subunit [ChIP-seq II]

The Integrator complex is one of the most elusive transcriptional regulators in metazoans, deemed to be recruited after initiation to help establish and modulate paused RNAPII. Recent structural, biochemical, and functional evidence suggest that Integrator is composed of 14 subunits, assembling, and operating in a modular fashion. We employed proteomics and machine-learning (alphafold2) approaches to discover a novel Integrator subunit, INTS15. We report that INTS15 assembles primarily with the INTS10-INTS13-INTS14 module and interfaces with the Int-PP2A phosphatase module. Functional genomics analysis further reveals a role for INTS15 in modulating RNAPII pausing at a subset of genes in human cell lines. C7orf26 (INTS15) was ChIPed in WT HeLa and HL-60 cells after stimulation. ChIP-seq for RNA polymerase II was done in HeLa cells that were treated with shRNAs for C7orf26 or Luciferase (control).