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生的机制。 近年来的研究表明，Tcf-3、VegT和我们正在研究的异种核因子7（xnf 7）等母体因子在胚胎生殖层的特化、模式化和分化中起着重要作用。 这些母体因素的影响是明显的，在晚期囊胚早期原肠胚阶段的区域特异性激活合子基因表达，使胚胎被分为各种子域。 最背侧区域形成Spemann组织者，其表达大量转录和分泌因子。这些在将组织器分为头部和躯干组织器区域的组织结构域中表达。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侧特异性基因表达模式的机制。 基于我们最近从这个实验室获得的数据，我们假设xnf 7是几个重要的母体因素之一，负责胚胎的背腹域的整体模式和背侧最多方面的组织者模式。 在下一个资助期，我们的目标是进一步确定xnf 7发挥作用的精确机制和分子途径，并利用xnf 7作为工具，深入了解胚胎模式化的一般机制和组织者如何形成和形成模式的具体细节。这将通过鉴定潜在的xnf 7靶基因，鉴定xnf 7的核伴侣，以及确定xnf 7在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.