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）作用于颅神经嵴细胞，并通过诱导同源异型基因Dlx 5和Dlx 6决定咽前弓的腹侧身份。2.我们发现ET-1信号激活了Dlx 5/6基因座的基因间元件m5/6 i的增强子活性，导致Dlx 5/6表达上调。我们还实现了转基因小鼠系统，其中任何感兴趣的基因可以有效地敲入ETAR基因座通过Cre重组酶介导的盒交换。利用该系统，我们可以敲入lacZ基因，从而明确鉴定表达ETAR的细胞。4.我们利用DNA微阵列技术鉴定了Capn 6是ET-1信号转导的下游基因。Capn 6可能通过调控微管网络参与细胞的分裂和形态。5.我们已经鉴定了TAZ，一种转录辅激活因子，是一种Pax 3结合蛋白。TAZ被发现共激活Pax 3的转录活性。TAZ-lacZ基因敲入小鼠已经在胚胎发生过程中鉴定了表达TAZ的细胞。TAZ-lacZ基因敲入小鼠的部分致死性表明了该基因在发育中的重要性。

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.