Evolution of Axial Patterning - Functional Approaches

描述(由申请人提供)： 本研究的目的是研究多细胞动物发育过程中关键调控基因在轴向区域化中的功能。这一目标属于解决后生动物分子构型机制基本问题的长期综合目标。在这项研究中，我们将使用功能遗传学分析来确定Hox/ParaHox基因在蛇类动物轴型中的作用。HoxlParaHox基因在三倍体动物前后构型中的保守功能决定了双侧动物的“动物型”。这些基因是否在蛇形目动物中发挥类似的作用仍有待确定。有几个具体的目标。在这项拟议的研究中。首先，从矢状线虫(线虫纲：珊瑚虫纲)中分离出一个后部ParaHox基因，并对其表达模式进行了研究。接下来，我们将使用两种互补的功能分析方法，即异位基因表达和基因沉默，来研究蚊虫Hox/ParaHox基因在发育过程中的功能。最后，我们将研究人类HOX/ParaHOX基因在再生过程中的功能，以阐明个体发育和再生机制之间的潜在同源性。确定线虫的Hox/ParaHox基因功能将使我们能够在线虫和双边动物之间建立轴向同源性。这些结果将揭示Hox和ParaHox基因在后生动物早期历史中的祖先作用，并将为复杂身体计划的进化提供有价值的见解。

DESCRIPTION (provided by applicant): The objective of this research is to investigate functions of key regulatory genes in axial regionalization during development of multicellular animals. This objective falls within the long-range comprehensive goal of addressing fundamental questions of molecular patterning mechanisms in metazoans. In this study, we will use functional genetic assays to determine the roles of the Hox/ParaHox genes in axial patterning in cnidarians. The conserved function of HoxlParaHox genes in anterioposterior patterning of triploblastic animals defines the bilaterian 'zootype'. Whether these genes perform comparable roles in cnidarians remains to be determined. There are several specific aims. In this proposed study. First, a posterior ParaHox gene will be isolated from Nematostella vectensis (Cnidaria: Anthozoa) and its expression pattern characterized. Next, the function of cnidarian Hox/ParaHox genes during development will be examined in N. vectensis using two complementary functional assays, ectopic gene expression and gene silencing. Finally, the function of cnidarian Hox/ParaHox genes during the process of regeneration will be examined to elucidate potential homology between the mechanistic events in ontogeny and regeneration. Determining Hox/ParaHox gene function in cnidarians will allow us to establish axial homologies between cnidarians and bilaterians. These results will reveal the ancestral roles of Hox and ParaHox genes in early metazoan history and will provide valuable insight to the evolution of complex body plans.