Evolution and Development of Vertebrate Hox14 Genes

本研究将调查迄今未知的类似性类群的脊椎动物Hox基因，Hox14。编码Hoxa14和Hoxd14的基因最近分别在腔棘鱼和板鳃中被发现，初步数据表明这些基因具有生物学功能。这些发现提出了许多与这些基因的进化和发展有关的问题。将追求四个具体目标。前两项是分别从七鳃鳗和肺鱼中克隆和基因组表征Hox14基因。已经设计了策略，以利用实验室在脊椎动物Hox基因的基因组分离和表征方面的专业知识。第三个目标将检查和比较Hox14基因在鳐鱼和七鳃鳗中的表达模式。为了评估Hox14在七鳃鳗胚胎发育中的直接作用，将在七鳃鳗中进行功能实验。第四个目标将描述和检查推定的顺式调控元件在Hoxa14和Hoxd14编码序列附近的发育作用。一个这样的元素已被证明是参与一个明确的和一致的表型在体内三个替代系统，从而加强了这一目的的基本原理。这四个具体目标是独立的，不是相互依存的。这项研究的首要目标是了解Hox14基因在脊椎动物进化和发育中可能发挥的作用。在脊椎动物中发现Hox14基因是出乎意料的，它们在大约4亿年前分化的不同脊椎动物谱系中保持不变，表明它们可能在发育中发挥了关键作用。这项研究的“广泛影响”可以从两个方面来衡量：(1)通过采用高度跨学科的方法来解决问题，包括基因组学、进化生物学、发育生物学和自然史；(2)提供丰富的研究和教育资源和机会。研究资源包括公开的基因库和其他试剂。培训机会包括为未被充分代表的少数民族的本科生提供实习机会。

This research will investigate a paralogous group of hitherto unknown vertebrate Hox genes, Hox14. Genes encoding Hoxa14 and Hoxd14 were recently discovered in the coelacanth and elasmobranchs, respectively, and preliminary data suggest that these genes are biologically functional. The findings raise numerous questions germane to the evolution and development of these genes. Four Specific Aims will be pursued. The first two are to clone and genomically-characterize Hox14 genes from the lamprey and lungfish, respectively. Strategies have been designed to take advantage of the laboratory's expertise in the genomic isolation and characterization of vertebrate Hox genes. The third Aim will examine and compare expression patterns of Hox14 genes in both the skate and the lamprey. Functional experiments will be undertaken in the lamprey in order to assess the direct role of Hox14 in embryological development. The fourth Aim will delineate and examine the developmental role of putative cis regulatory elements in the vicinity of the Hoxa14 and Hoxd14 coding sequences. One such element has been shown to be involved in a clear and consistent phenotype in vivo in three surrogate systems, thus strengthening the rationale for this Aim. The four Specific Aims are independent and not contingent on one another. The overarching goal of this research is to understand the role that Hox14 genes may have played in vertebrate evolution and development. The discovery of Hox14 genes in vertebrates was unexpected and their maintenance in distinct vertebrate lineages that diverged some 400 million years ago suggests that they may have played a key developmental role. The "broad impact" of this research is measured in two ways: (1) through employment of highly interdisciplinary approaches to problem solving, including genomics, evolutionary biology, developmental biology and natural history; and (2) by providing a wealth of research and educational resources and opportunities. The research resources include publicly available gene libraries and other reagents. The training opportunities include traineeships for undergraduates of underrepresented minorities.