Protein/nucleic Acid Interactions In Vertebrate Embryoge

在脊椎动物中，在原肠胚形成过程中，外胚层被细分为四个主要部分：表皮和中枢神经系统（CNS）分别位于腹面和背面，神经嵴和感觉基板位于这两个区域之间。该项目的目标是了解决定外胚层细胞如何在这些途径中选择的机制，以及如何调节随后的组织模式和分化，主要关注神经嵴。爪蟾神经嵴诱导需要两个信号，一个是部分衰减的BMP信号，另一个是Wnt/ β - catenin信号。我们发现转录因子TFAP2alpha负责将BMP信号传递到基因组，并激活广泛的神经嵴特异性基因。我们使用激素诱导型AP2alpha作为工具，结合微阵列分析来鉴定表皮和神经嵴中的靶基因。我们现在的研究重点是确定其中一小部分基因的功能。我们特别对两个感兴趣；一个是我们命名为“Inca”的基因（AP2诱导的神经嵴）。印加基因在青蛙、老鼠和斑马鱼中的序列和表达模式是保守的。在青蛙和斑马鱼中，我们使用反义寡核苷酸来证明印加是颅面软骨、骨骼和其他涉及神经嵴的组织正常发育所必需的。酵母双杂交分析发现，p21激活的激酶PAK4与Inca相互作用，支持Inca在神经嵴细胞迁移和分化过程中调节细胞骨架动力学的模型。另一个基因编码一种新的原钙粘蛋白PCNS，它是一种粘附分子，在神经嵴和发育体中短暂表达。PCNS缺失会导致神经嵴细胞迁移失败，也会导致体突和轴肌发育异常。由于这些基因在整个脊椎动物系统发育中都是保守的，我们期望我们的发现对生物医学研究和人类健康与发展具有广泛的相关性。

In vertebrates, the ectoderm is subdivided during gastrulation into four primary fates: epidermis and central nervous system (CNS) on the ventral and dorsal surfaces, respectively, and neural crest and sensory placodes located between these two domains. The goal of this project is to understand the mechanisms that determine how ectodermal cells choose among these pathways, and how the ensuing tissue patterning and differentiation are regulated, with a primary focus on the neural crest. Neural crest induction in Xenopus requires two signals, a partially attenuated BMP signal and a Wnt/beta catenin signal. We have found that the transcription factor TFAP2alpha is responsible for conveying the BMP signal to the genome, and activation of a broad spectrum of neural crest-specific genes. We used a hormone-inducible version of AP2alpha as a tool in conjunction with microarray analysis to identifiy target genes in both epidermis and neural crest. We are now focusing our research on determining the function of a small number of these genes. In particular, we are interested in two; one is a gene we named "Inca" (for Induced in Neural Crest by AP2). Inca is conserved in sequence and expression pattern in frogs, mice, and zebrafish. In the frog and zebrafish, we have used antisense oligonucleotides to show that Inca is required for proper development of the craniofacial cartilage and bones and other tissues where neural crest is involved. Yeast two-hybrid analysis has identified a p21-activated kinase, PAK4, as an interaction partner with Inca, supporting a model in which Inca functions to regulate cytoskeletal dynamics during neural crest cell migration and differentiation. Another gene encodes a novel protocadherin, PCNS, which is an adhesion molecule that is transiently expressed in neural crest and developing somites. Loss of PCNS results in failure of neural crest cell migration and also in abnormal somite and axial muscle development. Since these genes are conserved throughout vertebrate phylogeny, we expect our findings to broad relevance to biomedical research and human health and development.