RNA Seq analysis of neoblasts from Schmidtea mediterranea treated with RNAi against zfp1, p53, or unc22 to identify factors involved in neoblast differentiation.. Schmidtea mediterranea

Epidermis is essential for animal survival, providing both a protective barrier and cellular sensor to the external environment. Interestingly, the epidermes of different species show broad morphological and functional diversity yet it is unclear whether this diversity came from modification of an existing gene regulatory network or de novo innovation of new genes. Here we identify the transcriptional regulators underlying the differentiation program of planarian epidermal lineage. We classify Smed-p53 as the most upstream molecule in this transcriptional cascade, suggesting a potentially conserved role for this gene in epidermal differentiation similar to TP63 in vertebrates. Moreover, we find that homologs of Sox and Pax family transcription factors, Smed-soxP-3 and Smed-pax-5, act cooperatively to activate the expression of epidermal markers. Together, these data show that planarian epidermal differentiation is regulated by a combination of conserved elements (p53/p63), recruitment of a non-conventional transcription module (soxP-3/pax-5), and novel genes (prog); they also suggest that specialized adpatations, such as epidermal mucus-secretion, arise from complex changes to gene networks. This experiment aims to identify regulators involved in epidermal differentiation at the neoblast stage by using RNA Seq to examine transcriptional changes in neoblasts (X1 population) isolated from animals treated with zfp-1 or p53 dsRNA. Overall design: Examine gene expression profiles of FACS sorted X1 stem cell population from adult flatworms after 6, 9, and 13 days of treatment with RNAi against either zfp1, p53, or an unc22 non-targeting control. The experiment was performed in quadruplicate, with one discarded as an outlier for low sequence yield, resulting in 35 samples.