ADP-ribosylation of STAT1α by PARP-1 is Required for IFNγ-stimulated Transcriptional Responses in Macrophages [STAT1_ChIP-Seq_BMDM]

A key determinant of the pro-inflammatory responses in macrophages is the Signal Transducers and Activators of Transcription (STAT) family member, STAT1α. STAT1α activation by interferon-gamma (IFNγ) leads to induction of a transcriptional program that is coordinated in a large part by post-translational modifications such as phosphorylation. Poly(ADP-ribose) Polymerases (PARPs), which include PARP-1, catalyze the addition of ADP-ribose moieties (ADP-ribosylation) to target proteins and modulate their function. We found that PARP-1 mediates IFNγ-stimulated transcription by regulating genome-wide binding of STAT1α and its IFNγ-dependent phosphorylation. We identified STAT1α as a target of PARP-1 and found sites of ADP-ribosylation on its DNA-binding (DBD) and Transcription Activation (TA) domains. Surprisingly, ADP-ribosylation on the DBD and TA domains had distinct functional consequences on STAT1α transcriptional activity. Moreover, loss of ADP-ribosylation on either site led to diminished pro-inflammatory responses. These results suggest that PARP-1-driven ADP-ribosylation of STAT1α is a critical mediator of inflammation in macrophages. ChIP-seq was perfomed in bone marrow derived macrophages (BMDM) treated with Interferon gamma (IFNγ) with or without PARP inhibitor treatment. Please note that each processed data file was generated from both replicates and is linked to the corresponding rep1 sample records.