NF-?B transcriptionally perturbs p53 dynamics hampering DNA2repair.

Cells integrate multiple, often concurrent signals through intertwined genetic circuits whose dynamics14shape transcriptional programs and cell fate decisions. Among these, the tumor suppressor p53 and15the inflammatory transcription factor NF-?B are central regulators of stress responses and cancer16biology, yet their dynamic crosstalk under co-activation remains poorly characterized. Here, we combine17genetic engineering, single-cell live imaging, transcriptome analysis and mathematical modeling to18dissect the dynamic interplay between p53 and NF-?B. We find that co-activation of NF-?B by19inflammatory cytokines significantly enhances p53 accumulation and modulates the expression of p5320target genes, while leaving NF-?B dynamics largely unaltered. Mechanistically, we show that NF-?B21activation increasesTP53transcription, and mathematical modeling demonstrates that this22transcriptional upregulation is sufficient to account for the observed perturbation of p53 dynamics.23Functionally, NF-?B co-activation rewires p53-dependent transcriptional programs and impairs p53-24mediated DNA repair following genotoxic stress, an effect that is absent in NF-?B-deficient cells. Our25results uncover a transcriptionally mediated amplification of p53 signaling by NF-?B that results in26functional antagonism, highlighting how the dynamic crosstalk between stress-responsive transcription27factors shapes cellular outcomes in complex signaling environments. Overall design: RNA-seq analysis was performed in MCF-7 NF?B+ and NF?B- cells under untreated conditions and 16 hours after treatment with either 10Gy IR, TNF-?, or their combination. Each condition was represented by 4 technical replicates.