One factor, two safeguards: RUNX1 divides its labor across the regulatory genome.

Acute RUNX1 degradation in mammary epithelial cells reveals that RUNX1 coordinates enhancer-centered epithelial identity control with promoter-centered DNA-damage responsiveness.

• Why it matters: It addresses how a single transcription factor can preserve cell state while simultaneously managing DNA-damage responses, a key regulatory challenge.
• What they did: Fritz et al. used acute RUNX1 degradation to perturb RUNX1 function and map its regulatory roles across enhancers versus promoters.
• The result: The findings show RUNX1 divides its labor across the regulatory genome, linking epithelial identity maintenance to DNA-damage responsiveness.