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节早期胚胎发育的机制。最近的研究表明，一些母性因子，如Tcf-3、Vegt和我们正在研究的Xenopus核因子7(XNF7)，在胚胎生殖层的指定、构型和分化中起着重要的作用。这些母体因素的影响在胚泡晚期-原肠胚期通过区域特异性激活合子基因表达而明显，使得胚胎被分成各种亚域。最背侧的区域形成Spemann组织者，表达多种转录和分泌因子。这些在重叠的域中表示，这些域将组织者分为头部和主干组织者区域。此外，特定的基因组在腹侧区域表达。关键问题之一是了解母体遗传程序调节组织者和腹壁特异基因表达模式的机制。根据本实验室的最新数据，我们推测XNF7是导致胚胎向背侧/腹侧区域的全局模式以及背侧最侧面组织者模式的几个重要母性因素之一。我们在下一个宽限期的目标是进一步定义xnf7发挥作用的精确机制和分子途径，并将xnf7作为一个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的细节。这将通过确定潜在的xnf7靶基因；确定xnf7的核伙伴；以及确定xnf7在形成内胚层和外胚层模式中的作用来实现。

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.