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

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.

表皮（epidermis）对动物存活至关重要，兼具保护屏障与外界环境细胞感知的双重功能。值得关注的是，不同物种的表皮展现出广泛的形态与功能多样性，但目前尚不明确这种多样性究竟源于现有基因调控网络的改造，还是新基因的从头创制（de novo innovation）。本研究鉴定了涡虫（planarian）表皮谱系分化程序的核心转录调控因子：我们将Smed-p53确定为该转录级联反应中最上游的调控分子，提示该基因在表皮分化中可能扮演了与脊椎动物TP63相似的保守功能角色。此外，我们发现Sox家族与Pax家族转录因子的同源物Smed-soxP-3与Smed-pax-5可协同激活表皮标志物的表达。综上，本研究数据表明，涡虫的表皮分化受到三类因素的协同调控：保守元件（p53/p63）、非经典转录模块（soxP-3/pax-5）的招募，以及新基因（prog）；同时也提示，诸如表皮黏液分泌这类特化适应性特征，源于基因网络的复杂重塑。本实验采用RNA测序（RNA Seq）技术，分析经zfp-1或p53双链RNA（dsRNA）处理的动物所分离的成浆细胞（neoblast，X1群体）的转录组变化，旨在鉴定成浆细胞阶段参与表皮分化的调控因子。