Assessment of individual functions of Myc family genes

Myc 家族基因的个体功能评估

基本信息

批准号：
08044286
负责人：
KONDOH Hisato
金额：
$ 3.84万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08044286/
关键词：
N-myc L-myc C-myc KO mouse transcription embryo c-myc Ndr-1 Cre LoxP ES細胞

项目摘要

To check the possibility of functional redundancy between the N-myc and L-myc genes, we generated N^<+/->L^<-/-> as well as N-myc and L-myc double mutant mice (N^<-/->L^<-/->). N-myc and L-myc double mutant embryos showed an overall phenotype similar to ablating N-myc only in mice (N^<-/->L^<+/+> or N^<-/->L^<+/>). The results indicate that L-myc is not essential for embryonic development, and negates the notion of redundant functions between the N-myc and L-myc genes.To identify N-myc regulatory target genes we subtracted total cDNAs of mutant embryo from wild type cDNAs at 10.5 dpc and vice versa, and isolated cDNA of down-regulated mRNA in the mutants or of up-regulated mRNA species in the opposite combination. One of the N-myc downstream genes, Ndrl was studied in detail. The promoter of Ndrl gene was directly repressed by N-myc and Max heterodimer complex. In various embryonic organ rudiments an inverse relationship was found between the expression of N-myc and Ndrl, indicating that repression of the latter by the former is a regulation operating in embryogenesis.To address whether N-myc and c-myc have overlapping functions, we have introduced the c-myc coding region into the N-myc locus so that it comes under the regulation of N-myc. No heterozygous offspring were observed among 32 ES cell "fathered" pups. This is a strong indication that the embryos expressing c-myc from the N-myc locus die in utero or may not even be generated.

为了检查 N-myc 和 L-myc 基因之间功能冗余的可能性，我们生成了 N^<+/->L^</-/-> 以及 N-myc 和 L-myc 双突变小鼠 (N^ </-/->L^<-/->)。 N-myc 和 L-myc 双突变体胚胎表现出与仅在小鼠中消融 N-myc 相似的总体表型（N^<-/->L^<+/+> 或 N^<-/->L^<+ />）。结果表明，L-myc 对于胚胎发育不是必需的，并且否定了 N-myc 和 L-myc 基因之间冗余功能的概念。为了鉴定 N-myc 调控靶基因，我们从野生型中减去了突变体胚胎的总 cDNA。 10.5 dpc 的 cDNA，反之亦然，以及突变体中下调 mRNA 或相反组合中上调 mRNA 种类的分离 cDNA。对 N-myc 下游基因之一 Ndrl 进行了详细研究。 Ndrl基因的启动子被N-myc和Max异二聚体复合物直接抑制。在各种胚胎器官雏形中，发现 N-myc 和 Ndrl 的表达之间存在负相关关系，表明前者对后者的抑制是胚胎发生中的一种调节。为了解决 N-myc 和 c-myc 是否具有重叠功能，我们将c-myc编码区引入到N-myc基因座中，使其受到N-myc的调控。在 32 只 ES 细胞“父亲”幼崽中没有观察到杂合后代。这强烈表明从 N-myc 基因座表达 c-myc 的胚胎在子宫内死亡或什至可能无法生成。