is Required for Ectodermal Cell Differentiation During Planarian Regeneration.

Forkhead box (Fox) genes belong to the "winged helix" transcription factor superfamily. The function of some Fox genes is well known, such as the role of in controlling metabolism and longevity and in controlling differentiation of endodermal tissues. However, the role of some Fox factors is not yet well characterized. Such is the case of FoxK genes, which are mainly studied in mammals and have been implicated in diverse processes including cell proliferation, tissue differentiation and carcinogenesis. Planarians are free-living flatworms, whose importance in biomedical research lies in their regeneration capacity. Planarians possess a wide population of pluripotent adult stem cells, called neoblasts, which allow them to regenerate any body part after injury. In a recent study, we identified three paralogs in the genome of . In this study, we demonstrate that inhibition prevents regeneration of the ectodermal tissues, including the nervous system and the epidermis. These results correlate with expression in neoblasts and in neural progenitors. Although the triggering of wound genes expression, polarity reestablishment and proliferation was not affected after silencing, the apoptotic response was decreased. Altogether, these results suggest that would be required for differentiation and maintenance of ectodermal tissues.