Identification of new p63 targets in keratinocytes by ChIp on chip

p63 is a transcription factor required for the development and maintenance of ectodermal tissues, including skin, limb and, in general, multilayered epithelia. The identification of its target genes is fundamental for understanding the complex network of gene regulation governing the development of these epithelia. Our lab employed two strategies for this task: expression profiling of si RNA p63 depleted human keratinocytes (HaCat cells) (1) and ChIP on chIP analysis on two different platforms (CpG island and promoter arrays) with specific p63 antibodies in HaCat cells. We previously reported 186 high confidence p63 targets which were validated in different biological assays.(2). A re-analysis of the chip-chip data with less stringent criteria enlarged this list of putative targets to almost 1000 new locations. Independent chIP validations confirmed that around 60-70% of these new targets are bound by p63 in vivo and a subset of these genes are changing in expression during in vitro differentiation of primary human keratinocytes. Moreover, functional annotation of this extended list highlighted some unexpected GO terms enrichments such as heart development and nucleo- cytoplasmic transport. Detailed location analysis and functional studies are on going on these particular subclasses of genes to understand the physiological role of p63 in these processes.