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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，色素沉着主要在皮肤和眼睛中观察到，其中色素细胞存在。这种组织特异性黑素生成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，已知酪氨酸酶在7号染色体上的c基因座处编码，并且该基因的缺陷导致无黑素表型。我们已经证明小鼠酪氨酸酶基因5'上游2.6kb的序列在转基因小鼠中负责小鼠酪氨酸酶cDNA的细胞类型特异性表达，并试图寻找在其他哺乳动物中参与细胞类型特异性表达的任何元件。在本实验中，我们构建了一个融合基因，它包含了1.0 kb的5'侧翼序列的人酪氨酸酶基因与小鼠酪氨酸酶cDNA连接。将融合基因导入白化病小鼠的受精卵中，获得转基因小鼠，并分析了转基因小鼠的表达模式。我们获得了两只在皮肤和眼睛中表现出色素沉着的小鼠，并从其中一只小鼠中建立了转基因品系。在该品系的动物中，尽管发现转基因整合在所有检查的组织中，但仅在眼睛和毛囊中发现黑素生成。因此，似乎人酪氨酸酶基因的1.0 kb 5'上游区含有小鼠和人中基因的细胞类型特异性表达所必需的保守顺式元件。然而，在某些组织中，酪氨酸酶活性和酪氨酸酶mRNA的检测。小鼠细胞中可能存在细胞类型特异性转录后调控机制。