Roles of Hox genes in skin and hair follicle development

描述(申请人提供)：HOX转录调节因子在哺乳动物发育中扮演重要角色。虽然它们在皮肤及其附件的发育和再生中的作用目前还没有得到充分的研究，但这一点正受到越来越多的关注。一个值得注意的例子是Hoxc13，它对正常的毛囊发育是必不可少的。我们建立的HOXC/3过表达转基因小鼠和Hoxc13缺失小鼠都表现出严重的毛发生长缺陷，导致脱发。对转基因小鼠的DMA芯片分析和随后的各种方法验证确定Foxq1和Foxn1(在裸鼠和绸缎中突变)、原癌基因JunB、桥粒钙粘蛋白基因Dsc2和几个毛发角蛋白基因被认为是Hoxc13调控的靶点。我们的结果支持Hoxc13在控制毛囊分化的复杂调控网络中发挥核心作用的假设。确定这个网络对于了解许多皮肤和毛发疾病的机制至关重要，这些疾病包括导致脱发和一些皮肤癌的疾病。我们的总体目标是：1)确定Hoxc13是否与特定的靶基因直接相互作用。控制元件将通过DNA结合、共转染和染色质免疫沉淀分析以及体内Hoxc13依赖的调节来确定，使用报告基因分析在转基因和空白小鼠中都是如此。2)我们将确定Hoxc13和Foxg1蛋白是协同还是独立调节可能的共同靶基因。我们将在体外测试Dsc2启动子区域假定的Foxq1和Hoxc13结合位点的功能，并确定这些结合位点是否在共转染实验中介导潜在的合作/协同反应。3)最后，我们将确定毛囊分化所必需的依赖于Hoxc13的调控基因网络。比较纵向DNA微阵列分析将使用转基因小鼠和空白小鼠的皮肤样本，并在5个时间点进行适当的对照。这些数据将定义Hoxc13在毛囊发育的不同形态发生阶段过度表达或不表达的影响。使用独创性网络分析(C)和其他生物信息学工具将使我们能够开发一个由Hoxc13控制的调控毛囊分化的遗传网络的概念框架。与公共卫生相关：我们正在定义一个控制哺乳动物毛囊和毛干发育的基因网络。这些基因中的任何一个或所有的突变都会导致各种类型的脱发，其中许多与特定的人类皮肤病相同。我们的目标是确定这些基因是如何相互作用的，这最终将决定如何从疗法上处理这些疾病。

DESCRIPTION (provided by applicant): Hox transcriptional regulators play important roles in mammalian development. While their role in the development and regeneration of skin and its appendages is currently understudied, this is receiving increasing attention. A notable case is Hoxc13, which is essential for normal hair follicle development. Both hoxc/3-overexpressing transgenic mice created by us and Hoxc13 null mice exhibit severe hair growth defects resulting in alopecia. DMA microarray analysis of the transgenic mice and subsequent validation by various methods identified Foxql and Foxnl (mutated in nude and satin), proto-oncogene Junb, desmosomal cadherin gene Dsc2, and a several hair keratin genes as putative targets of Hoxc13 regulation. Our results support the hypothesis that Hoxc13 plays a central role in a complex regulatory network controlling hair follicle differentiation. Defining this network is critical for understanding mechanisms involved in numerous skin and hair diseases, including diseases that result in alopecia and some skin cancers. Our overall aims are to 1) determine whether Hoxc13 directly interacts with specific target genes. Control elements will be defined by DNA binding, co-transfection and chromatin immunoprecipitation assays, and Hoxc13-dependent regulation in vivo using reporter gene analysis in both transgenic and null mice. 2) We will determine whether Hoxc13 and Foxgl proteins regulate putative common target genes either cooperatively or independently. We will test functionality of putative Foxql and Hoxc13 binding sites in the promoter region of Dsc2 as a paradigm in vitro, and determine whether these mediate potential cooperative/synergistic responses in co-transfection assays. 3) Lastly, we will define Hoxc13-dependent regulatory gene networks essential for hair follicle differentiation. Comparative longitudinal DNA microarray analysis will be done using skin samples from both transgenic and null mice with appropriate controls at 5 time points. These data will define the effect of over- or nonexpression of Hoxc13 at distinct morphogenetic stages of hair follicle development. Use of Ingenuity Network Analysis(c) and other bioinformatics tools will allow us to develop a conceptual framework of a Hoxc13-controlled genetic network regulating hair follicle differentiation. Relevance to Public Health: We are defining a gene network that controls development of hair follicles and hair shafts in mammals. Mutations in any or all of these genes result in a various types of alopecia, many of which are identical to specific human skin diseases. Our goal is to determine how these genes interact with each other, which will ultimately define how these diseases can be approached therapeutically.