Protein/nucleic Acid Interactions In Vertebrate Embryoge

在脊椎动物中，与其他动物一样，外胚层有两个主要的命运，表皮和中枢神经系统（CNS）。该项目的目标是了解决定外胚层细胞如何在这两种途径之间进行选择的机制，以及如何调节随后的组织模式和分化。骨形态发生蛋白（BMPs）的信号传导是两栖动物胚胎表皮发育的主要启动事件。该实验室采取的实验方法是使用依赖于这种信号作为鉴定可能调节表皮/神经发育程序的基因的标准。注意力集中在远端同源物Dlx 3、5和6以及转录激活因子AP-2上。其他基因正在寻找使用消减杂交/微阵列技术。我们已经发现，这三个Dlx基因的差异调节BMP信号的分级响应，这可以解释至少一些的Dlx基因在原肠胚表达的空间模式的主要特征。DLX 3似乎参与建立颅神经嵴诱导的侧向边界，其方式类似于我们先前发现的该基因的抗神经特性。有趣的是，这种抑制功能似乎并不涉及Dlx 3对转录的直接调节，而是更可能依赖于蛋白质-蛋白质相互作用。Dlx 5和Dlx 6的作用仍然不清楚，但这个同源异型盒基因亚家族的功能解释胚胎中的形态发生梯度的可能性非常有趣。AP 2表达是BMP依赖性的，并且该因子的过度表达可以拯救BMP失能的外胚层中的表皮基因活性的发现也是非常有趣的，因为该基因在几年前被我们的实验室鉴定为潜在的表皮调节因子，使用启动子分析方法。我们还发现AP 2在神经嵴细胞的发育中起重要作用，目前正在蛋白质-蛋白质水平上研究AP 2、Dlx 3等因子之间的相互作用，并利用微阵列分析寻找受这些因子调控的靶基因。

In vertebrates, as in other animals, the ectoderm has two primary fates, epidermis and central nervous system (CNS). The goal of this project is to understand the mechanisms that determine how ectodermal cells choose between these two pathways, and how the ensuing tissue patterning and differentiation are regulated. It has been well established that signaling by bone morphogenetic proteins (BMPs) is the primary event that initiates epidermal development in the amphibian embryo. The experimental approach taken by this laboratory has been to use dependence upon such signaling as a criterion for identifying genes that may regulate the epidermal/neural developmental program. Attention has been focused on the Distal-less homologs Dlx3, 5 and 6 and on the transcriptional activator AP-2. Additional genes are being sought using subtractive hybridization/microarray techniques. We have found that the three Dlx genes are differentially regulated by a graded response to BMP signaling, and that this can account for at least some of the major features of the spatial pattern of Dlx gene expression in the gastrula. Dlx3 appears to be involved in establishing the lateral boundary of cranial neural crest induction, in a manner similar to the anti-neural properties we previously discovered for this gene. Interestingly, this inhibitory function does not appear to involve direct regulation of transcription by Dlx3, but is more likely dependent upon protein-protein interactions. The roles of Dlx5 and Dlx6 remain obscure, but the possibility that this subfamily of homeobox genes function to interpret a morphogenetic gradient in the embryo is very intriguing. The findings that AP2 expression is BMP-dependent, and that over-expression of this factor can rescue epidermal gene activity in BMP-disabled ectoderm are also highly interesting, as this gene was identified by our laboratory several years ago as a potential epidermal regulatory factor, using a promoter analysis approach. We have also found that AP2 plays an important role in the development of neural crest cells, and are now examining the interactions between AP2, Dlx3 and other factors at the protein-protein level, and using microarry analyis to search for target genes regulated by these factors.