Horng Ou is a Senior Scientist at Replay. A structural biologist by training, he has broad interests in how structures determine functions at the molecular and cellular level. He obtained his Ph.D at University of California, San Francisco with Dr. Volker Doetsch, and post-doctoral training with Dr. Clodagh O’Shea at the Salk Institute for Biological Studies. As a post-doctoral fellow, he solved the structure of an Adenoviral protein E4-ORF3 and proposed a model of viral polymer assembly, which can induce heterochromatin assembly and prevent p53 induced gene activation. He also developed the ChromEMT (chromatin EM-Tomography) technique in collaboration with Dr. Ellisman’s lab at University of California, San Diego, to paint chromatin structures in-situ to reveal chromatin organization of mitotic and interphase cells that further supports the model that chromatin is packaged as 10-nm polymer instead of classical hierarchical higher order structures. The high resolution of EM-Tomography reveals chromatin structures as disordered polymer that packed in various density which could explain regions of gene activation and silencing.