PATTERN FORMATION DURING EARLY XENOPUS DEVELOPMENT

含有同源异型盒的基因是一个基因家族， 果蝇在发育过程中控制图案的形成。 这些基因 编码以序列特异性方式与DNA结合的蛋白质。 他们 含有一个180 bp的保守DNA结构域，称为同源框。 我们已经分离出 几个同源框包含在早期非洲爪蟾 发展 我们已经确定了它们的时空表达 使用北方印迹分析和原位杂交的模式。 至少 其中一些基因在原肠胚形成期间表达， 中胚层和神经诱导发生的发育时期 地方 对这些基因的序列分析表明，其中一些基因是 与先前在其它物种如小鼠中描述的基因同源 和果蝇，其他的还没有被描述过。 其中一个新 同源盒基因XDLL-1与果蝇Distal-less基因同源 家人 它在胚胎的粘液腺、神经嵴中表达 衍生的内脏弓和前脑。 它的时空表达 模式表明，该基因涉及前脑和颅- 面部发育 除了同源异型盒基因家族， 分离出叉头基因家族的新成员 个别成员 这个家族的成员有一个非常有趣的表达模式，至少 有些是致癌基因。 第一个非洲爪蟾叉头基因XFKH 1具有 许多非常有趣的特征。 它被激活时，或不久之后， 在胚胎的背侧边缘骨中的中囊胚过渡。 在 在原肠胚早期，它仅限于组织者区。 在以后阶段 它在脊索和神经底板中表达。 而且 在分离的动物帽中可被激活素诱导。 其表达模式 而激活素的诱导表明，该基因具有关键的 非洲爪蟾胚胎早期模式形成的重要性。

Homeobox containing genes are a family of genes which have been shown in Drosophila to control pattern formation during development. These genes encode proteins which bind to DNA in a sequence specific manner. They contain a 180 bp conserved DNA domain called a homeobox. We have isolated several homeobox containing genes which are activated during early Xenopus development. We have determined their temporal and spatial expression pattern using Northern blot analysis and in situ hybridization. At least some of these genes are expressed during gastrulation, a critical time period of development at which mesodermal and neural induction takes place. Sequence analysis of these genes revealed that some of them are homologous to previously described genes in other species such as mouse and Drosophila, others have not yet been described. One of the new homeobox genes, the XDLL-1, is homologous to Drosophila Distal-less gene family. It is expressed in the embryonic cement gland, neural crest derived visceral arches and forebrain. Its temporo-spatial expression pattern indicates that this gene is involved in forebrain and cranio- facial development. In addition to the homeobox gene family we have isolated new members of the Fork head gene family. The individual members of this family have a highly interesting expression pattern and at least some of them are oncogenes. The first Xenopus Fork head gene XFKH1 has many highly interesting features. It is activated at, or shortly after, the midblastula transition in the dorsal marginal bone of the embryo. In early gastrulae it is restricted to the organizer region. At later stages it is expressed in the notochord and neural floor plate. Furthermore, it is inducible by activin in isolated animal caps. Its expression pattern and inducibility by activin suggests that this gene has a critical importance for early pattern formation in Xenopus embryos.