Fig 2: Feed-forward model of megadomain formation. BRD4-NUT is tethered to acetylated chromatin by BRD4 bromodomains. The NUT portion of the fusion protein recruits p300, leading to increased local histone acetylation and thus a self-perpetuating recruitment of BRD4-NUT. The ultimate result is uncontrolled spreading of BRD4-NUT across chromatin, forming megadomains that typically are limited only by TAD boundaries.

Fig 3: Micrograph images of an abdominal lymph node section immunohistochemistry derived from the patient with nuclear protein in testis (NUT) midline carcinoma. Immunoreactivity is indicated by the dark-brown staining from oxidized diaminobenzidine chromogen used in the method. The blue counterstain is Mayer's hematoxylin. A. Positive cytoplasmic immunoreactivity for cytokeratin (AE1/AE3), 200× (scale bar 50 μm). B. Positive cytoplasmic immunoreactivity for epithelial membrane antigen, 200× (scale bar 50 μm).

Fig 4: NUT-positive controls from testis (a) and one previously confirmed NUT midline carcinoma (b). NUT-negative lung carcinoma tissue (c, d)

Fig 5: BI 894999 and the detaching of BRD-NUT from chromatin.a Structure of the oral BET inhibitor BI 894999. b Immunofluorescence staining of NUT megadomains on the NC cell line Ty-82 treated with BET inhibitors for 30 min. BRD4-NUT detaches from chromatin with 10–30 nM BI 894999 (speckled staining changes to fuzzy staining).