SPEMANN'S ORGANIZER ACTIVITY AND HOMEOBOX GENES

一个同源异型盒基因goosecoid，在背侧囊胚孔中特异表达 唇是孤立的。 Goosecoid，特别有趣，因为它是：1） 由激活素（一种中胚层诱导生长因子）直接激活，2） 特异性表达于唇背区的中胚层，3）仅 在原肠胚形成过程中表达，以及4）能够诱导 当注射到早期胚胎的卵裂球中时的次级轴。 这些 类鹅同源盒基因的特性表明， 在原肠胚形成过程中的基本调节作用。 将使用原位和原位杂交技术研究goosecoid的表达模式。 杂交和抗体染色技术。 为了解 类鹅同源结构域蛋白的功能，各种表达 将构建体显微注射到胚胎的单个卵裂球中 分析goosecoid基因的表达对细胞命运的影响。 将尝试获得功能丧失、功能获得和 显性失活突变体，通过显微注射抗体，正义和反义 RNA和寡核苷酸。 为了了解激活素介导的 信号转导途径，类鹅启动子报告基因构建 将被显微注射到胚胎中， 确定了goosecoid启动子。 因此，识别和 介导信号转导的分子的表征可以 完成了 将尝试分离goosecoid靶基因 使用从类鹅显微注射胚胎获得的差异探针。

A homeobox gene goosecoid, specifically expressed in the dorsal blastopore lip was isolated. Goosecoid, is particularly interesting since it is: 1) directly activated by activin (a mesoderm-inducing growth factor), 2) specifically expressed in the mesoderm of dorsal lip region, 3) only expressed during the gastrulation process, and 4) capable of inducing a secondary axis when injected into a blastomere of an early embryo. These properties of the goosecoid homeobox gene suggest that the gene plays fundamental regulatory roles during gastrulation. Expression pattern of goosecoid will be studied using both in situ hybridization and antibody staining techniques. In order to understand the function of the goosecoid homeodomain protein, various expression constructs will be microinjected into an individual blastomere of embryos to analyze the cell fate change brought by the expression of goosecoid. Attempts will be made to obtain loss-of-function, gain-of-function, and dominant-negative mutants by microinjecting antibodies, sense and antisense RNAs and oligonucleotides. In order to understand the activin-mediated signal transduction pathway, goosecoid promoter reporter gene constructs will be microinjected into embryos and the activin responsive element in the goosecoid promoter identified. Thus, the identification and characterization of the molecules mediating the signal transduction can be accomplished. Isolation of the goosecoid target genes will be attempted using differential probes obtained from goosecoid microinjected embryos.