Patterning of the Embryonic Germ Layers

发育生物学中的一个基本问题涉及母体程序调控早期胚胎发生的机制。最近的研究表明，一些母体因子如Tcf-3、VegT和Xenopusnuclear factor 7 (xnf7)，在胚胎种层的规范、模式和分化中起着重要作用，我们正在研究xnf7基因。这些母体因素的影响在囊胚晚期-原胚早期通过合子基因表达的区域特异性激活而明显，从而使胚胎分为各种亚域。最背侧的区域形成Spemann组织者，表达多种转录因子和分泌因子。这些表达在重叠的区域，将组织者分为头部和躯干组织者区域。此外，特定的基因群在腹侧区域表达。其中一个关键问题是了解母体遗传程序调节组织者和腹侧特异性基因表达模式的机制。根据我们实验室最近的数据，我们假设xnf7是几个重要的母性因素之一，负责胚胎进入背/腹域的整体模式和背部大多数方面的组织者模式。在下一个资助期内，我们的目标是进一步定义xnf7发挥作用的精确机制和分子途径，并使用xnf7作为工具来深入了解胚胎模式的一般机制以及组织者如何形成和模式化的细节。这将通过识别潜在的xnf7靶基因来实现；确定xnf7的核伙伴；并确定xnf7在内胚层和外胚层形成中的作用。

A fundamental problem in developmental biology concerns the mechanism by whichthe maternal program regulates early embryogenesis. Recent studies havedemonstrated that several maternal factors such as Tcf-3, VegT, and Xenopusnuclear factor 7 (xnf7), a gene that we are studying, play important roles inthe specification, patterning, and differentiation of the embryonic germlayers. The effect of these maternal factors is evident at the lateblastula-early gastrula stage by the region specific activation of zygotic geneexpression such that the embryo is divided into a variety of subdomains. Themost dorsal region forms the Spemann organizer which expresses a large varietyof transcription and secreted factors. These are expressed in overlappingdomains that divide the organizer into the head and trunk organizer regions. Inaddition specific groups of genes are expressed in the ventral region. One ofthe key problems is to understand the mechanism by which the maternal geneticprogram regulates the pattern of expression of both the organizer and ventralspecific genes. Based on our recent data from this laboratory we hypothesizethat xnf7 is one of several important maternal factors responsible for theglobal patterning of the embryo into dorsal/ventral domains and for patterningof the organizer in the dorsal most aspect. Our goal during this next grantperiod is to further define the precise mechanisms and molecular pathway throughwhich xnf7 functions and to use xnf7 as a tool to gain insights into the generalmechanisms of embryonic patterning and the specifics of how the organizer formsand is patterned. This will be accomplished by identifying potential xnf7 targetgenes; identifying nuclear partners of xnf7; and determining the role of xnf7in patterning endoderm and ectoderm.