Disrupted transcripitonal network in ΔNp63 AEC tissue model [gene expression]

The transcriptional basis for disrupted epidermal differentiation arising from TP63 AEC mutations remains to be elucidated. Here we present an organotypic model of AEC dysfunction that phenocopies differentiation defects observed in AEC patient skin. Transcriptional analysis of model AEC tissue revealed impaired induction of differentiation regulators, including OVOL1, GRHL3, KLF4, PRDM1 and ZNF750. Genome wide binding analyses of TP63 during epidermal differentiation showed direct binding of OVOL1, GRHL3, and ZNF750 promoters suggesting AEC mutants prevent normal activation of these targets by direct transcriptional interference. Remarkably, exogenous ZNF750 restores impaired epidermal differentiation caused by AEC mutation. Thus, repression of ZNF750 is central to disrupted epidermal differentiation in model AEC tissue. Gene expression analysis: To establish a differentiation signature for primary human keratinocytes, with p63i-depleted, and ΔNp63α AEC mutants overexpressed, total RNA was isolated in biologic duplicate from cells in different conditions and hybridized to Affymetrix HG-U133 2.0 Plus arrays.