NRL and retinoblastoma: Ectopic expression of CRX in cultured HEK293 and Y79 retinoblastoma cells failed to produce a rod-like epigenome, even with co-expression of NRL (Ruzycki and Chen, unpublished results), suggesting CRX is not a “pioneer” factor that can bind to fully closed sites to induce de novo chromatin remodeling for cell fate specification.