Abstract Over 95% of ependymomas that arise in the cortex are driven by a gene fusion involving the zinc finger translocation-associated (ZFTA) protein. Here, using super-resolution and lattice light-sheet microscopy, we demonstrate that the most frequent fusion variant, ZFTA–RELA (ZR), forms dynamic nuclear condensates that are required for oncogene expression and tumorigenesis. Mutagenesis studies of ZR reveal a key intrinsically disordered region (IDR) in RELA that governs condensate formation.
