ADP-ribosylation of STAT1a by PARP-1 is Required for IFN?-stimulated Transcriptional Responses in Macrophages [iBMDM_Stat1_mutant_RNAseq]

A key determinant of the pro-inflammatory responses in macrophages is the Signal Transducers and Activators of Transcription (STAT) family member, STAT1a. STAT1a activation by interferon-gamma (IFN?) 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 IFN?-stimulated transcription by regulating genome-wide binding of STAT1a and its IFN?-dependent phosphorylation. We identified STAT1a 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 STAT1a 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 STAT1a is a critical mediator of inflammation in macrophages. Overall design: RNA-seq was perfomed in immortalized bone marrow derived macrophages (iBMDM) expressing wildtype or ADP-ribosylation deficient mutants. Please note that each processed data file was generated from both replicates and is linked to the corresponding rep1 sample records.