miR-203 regulates progenitor cell proliferation during adult zebrafish retina regeneration.
In a rich and comprehensive piece of work, Ferone et al report in this issue of EMBO Molecular Medicine the first mouse model of the AEC (Ankyloblepharon-Ectodermal defects-Cleft lip/ palate, OMIM 106260) syndrome (Ferone et al, 2012). The mechanistic insights are of likely general relevance for a number of conditions resulting from deranged keratinocyte growth control, including cancer. AEC is part of a group of genetic syndromes with compromised skin development that go under the general name of ectodermal dysplasias (EDs). These are caused by mutations of genes with disparate functions, including transcription factors like p63. This close cousin of p53 plays a key role in ectodermal development as first demonstrated by the lack of stratified epithelia and their adnexa inmicewith homozygous deletion of the gene. Importantly, no such alterations occur inmicewith heterozygous p63 deletion, which are phenotypically normal. In the human population, at least five ED malformation syndromes have been linked to p63 gene mutations (Rinne et al, 2006). These are heterozygous missense mutations likely to cause the disorders by interfering with the function of wild type p63, which controls transcription by