Genome-wide binding of WDR5 and GRHL3. Homo sapiens

The antagonistic actions of Polycomb and Trithorax are responsible for proper cell fate determination in mammalian tissues. In the epidermis, a self-renewing epithelium, previous work has shown that release from Polycomb repression only partially explains differentiation gene activation. We now show that Trithorax is also a key regulator of epidermal differentiation, not only through activation of genes repressed by Polycomb in progenitor cells, but also through activation of genes independent of regulation by Polycomb. The differentiation associated transcription factor GRHL3/GET1 recruits the ubiquitously expressed Trithorax complex to a subset of differentiation genes. Overall design: Examination of WDR5 and GRHL3 binding in human differentited primary keratinocytes (NHEK). High calcium medium was added to NHEK cells at 50% confluency to induce differentiation. Cells were collected for ChIP 24 hours after addition of high calcium medium. ChIP with Wdr5 and Grhl3 antibodies, and an input control were sequenced.