Molecular cascades underlying the integration of cell differentiation and morphogenesis in cranial/cardiac neural crest development

1.我们发现，由咽上皮和核心中胚层产生的内皮素-1通过ET-A受体(ETAR)作用于颅神经脊细胞，并通过诱导同源基因D1x5和Dlx6决定咽前弓的腹侧特性。经ET-1的区域定位后，Dlx5/6的表达由成纤维细胞生长因子信号维持。2.我们发现ET-1信号激活了Dlx5/6基因座的间隔区元件M5/6i的增强子活性，导致Dlx5/6的表达上调。3.我们建立了在Etar基因启动子下表达GFP的小鼠，以可视化表达Etar的细胞。我们还实现了转基因小鼠系统，在该系统中，任何感兴趣的基因都可以通过Cre重组酶介导盒交换有效地插入Etar基因座。利用这个系统，我们可以通过敲入lacZ基因来明确鉴定表达Etar的细胞。4.我们利用DNA芯片鉴定了Capn6是ET-1信号转导下游的一个基因。Capn6可能通过调节微管网络参与细胞的分裂和形态。5.我们鉴定了转录共激活因子TAZ是一种Pax3结合蛋白。TAZ被发现共激活了Pax3的转录活性。Taz-LacZ敲入小鼠已发现在胚胎发育过程中表达TAZ的细胞。TAZ-LacZ基因敲除小鼠的部分致死率表明了该基因在发育过程中的重要性。

1.We have found that endothelin-1, produced by pharyngeal epithelium and core mesoderm, acts on cranial neural crest cells via ET-A receptor (ETAR) and determines the ventral identity of the anterior pharyngeal arches by inducing homeotic genes Dlx5 and Dlx6. After the regional specification by ET-1, Dlx5/6 expression was proved to be maintained by the FGF signaling.2.We have found that the ET-1 signaling activates the enhancer activity of m5/6i, the intergenic element of the Dlx5/6loci, leading to the upregulation of Dlx5/6 expression.3.We have established mice expressing GFP under the ETAR gene promoter to visualize the ETAR-expressing cells. We also realized the transgenic mouse system in which any genes of interest can be efficiently knocked-in into the ETAR locus by Cre recombinase-mediated cassette exchange. Using this system, we could knock-in the lacZgene to definitely identify the ETAR-expressing cells.4.We have identified Capn6 as a gene downstream to the ET-1 signaling using DNA microarray. Capn6 was found to be possibly involved in cell division and morphology through the regulation of microtubular networks.5.We have identified TAZ, a transcriptional coactivator, as a Pax3-binding protein. TAZ was found to coactivate the transcriptional activity of Pax3. TAZ-lacZ knock-in mice have identified TAZ expressing cells during embryogenesis. Partial lethality of TAZ-lacZ knock-in mice has indicated the importance of this gene in development.