Studies on the mechanism of tissue-specific gene expression by the use of transgenic mice.

利用转基因小鼠研究组织特异性基因表达的机制。

基本信息

批准号：
03640536
负责人：
TAKEUCHI Takuji
金额：
$ 1.28万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

In vertebrates, pigmentation is observed mainly in skin and eyes where pigment cells exist. This tissue-specific melanogenesis is considered to involve cell type specific expression of the tyrosinase gene. In mice, it is known that tyrosinase is encoded at the c-locus on chromosome 7 and that deficiency of the gene results in an amelanotic phenotype. We have shown that sequences in the 2.6-kb 5' upstream region of the mouse tyrosinase gene are responsible for cell type-specific expression of the mouse tyrosinase cDNA in the transgenic mice.An attempt was made to find any element that is involved in the cell type-specific expression in other mammals. In the present experiment, we constructed a fused gene which contains the 1.0-kb 5' flanking sequence of the human tyrosinase gene ligated with the mouse tyrosinase cDNA. By introducing the fused gene into fertilized eggs of albino mice, we obtained transgenic pigmented mice and analyzed the expression pattern of the transgene. We obtained two mice that exhibited pigmentation in the skin and eyes, and established a transgenic lines from one of them. In the animals of the line, melanogenesis was found only in eyes and hair follicles though the transgenes were found integrated in all tissues examined. Therefore, it seems that the 1.0-kb 5' upstream region of the human tyrosinase gene contains conserved cis-elements essential for cell type-specific expression of the genes in mice and humans. In some tissues, however, tyrosinase activity and tyrosinase mRNA were detected. It seems possible that a cell type-specific post-transcriptional regulation mechanism is present in the mouse cells.

在脊椎动物中，色素沉着主要观察到存在着色素细胞的皮肤和眼睛。该组织特异性黑色素发生被认为涉及酪氨酸酶基因的细胞类型特异性表达。在小鼠中，众所周知，酪氨酸酶是在7号染色体上的C-cocus上编码的，并且该基因的缺乏会导致肿瘤性表型。我们已经表明，小鼠酪氨酸酶基因的2.6-Kb 5'上游区域中的序列负责转基因小鼠中小鼠酪氨酸酶cDNA的细胞类型特异性表达。在本实验中，我们构建了一个融合基因，其中包含与小鼠酪氨酸酶cDNA连接的人酪氨酸酶基因的1.0 kb 5'侧翼序列。通过将融合基因引入白化小鼠的受精卵中，我们获得了转基因色素小鼠，并分析了转基因的表达模式。我们获得了两只小鼠，它们在皮肤和眼睛中表现出色素沉着，并从其中一只中建立了转基因线。在这条线的动物中，尽管发现转基因在所有检查的组织中都集成了转基因，但黑色素发生仅在眼睛和毛囊中。因此，似乎人酪氨酸酶基因的1.0-kb 5'上游区域包含对小鼠和人类基因细胞类型特异性表达必不可少的保守的顺式元素。然而，在某些组织中，检测到酪氨酸酶活性和酪氨酸酶mRNA。小鼠细胞中似乎存在一种细胞类型特异性的转录后调节机制。