GENETIC ANALYSIS OF FGF-5 PROTO-ONCOGENE FUNCTION

FGF-5原癌基因指定一种分泌的生长因子， 与原型成纤维细胞生长因子序列同源。FGF-5。是 在几种胚胎环境中表达，在成熟的大脑中表达，在一些 肿瘤细胞这个应用程序提出了一系列的遗传实验 以确定FGF-5的许多独特功能。我们将破坏一个或 小鼠全能胚胎干细胞（ES）中FGF-5基因的两个等位基因 同源重组的细胞。将分析FGF-5阴性ES细胞 对于体外作为胚状体的分化潜力和作为肿瘤的分化潜力， vivo. FGF-5半合子ES细胞将被注射到胚泡中，以衍生 嵌合小鼠，并在生殖系中建立破坏的等位基因。近亲繁殖 以确定FGF-5的发育异常 阴性胚胎我们还将建立转基因小鼠， FGF-5基因在发育过程中的一个亚群中表达， 特征性位点或在结构域中具有结构突变的 目前未知的功能将这些转基因菌株与FGF-5交配 半合子小鼠和具有半合子品系的回交后代将 产生携带转基因作为唯一功能等位基因的胚胎。的 这些胚胎的异常表型将进一步剖析FGF-5的功能。 最后，我们将产生携带人FGF-5转基因的小鼠， 已知增加FGF-5 mRNA翻译效率的位点。这些 小鼠应过表达FGF-5蛋白而无异位表达， 由此产生的异常也将有助于确定FGF-5的功能。这些小鼠 还应监测癌症易感性。

The FGF-5 proto-oncogene specifies a secreted growth factor which bears sequence homology to the prototypic fibroblast growth factors. FGF-5. is expressed in several embryonic settings, in mature brain, and in some neoplastic cells. This application proposes a series of genetic experiments to determine many of FGF-5's distinct functions. We shall disrupt one or both alleles of the FGF-5 gene in murine totipotent embryonic stem (ES) cells by homologous recombination. FGF-5 negative ES cells will be analyzed for differentiation potential as embryoid bodies in vitro and as tumors in vivo. FGF-5 hemizygous ES cells will be injected into blastocysts to derive chimeric mice and establish a disrupted allele in the germ line. Inbreeding will be performed to determine the developmental abnormalities in FGF-5 negative embryos. We shall also establish transgenic mice bearing human FGF-5 genes which are expressed in a subset of the developmentally characteristic sites or which bear structural mutations in a domain of currently unknown function. Mating these transgenic strains with FGF-5 hemizygous mice and backcrossing progeny with the hemizygous strain will generate embryos carrying the transgenes as sole functional allele. The aberrant phenotypes of these embryos will further dissect FGF-5 function. Lastly, we shall generate mice carrying human FGF-5 transgenes mutated at sites known to increase the translation efficiency of FGF-5 MRNA. These mice should overexpress FGF-5 protein without ectopic expression, and resulting abnormalities will also help determine FGF-5 function. These mice shall also be monitored for cancer predisposition.