A transgenic mouse model with inducible Tyrosinase gene expression using the tetracycline (Tet-on) system allows regulated rescue of abnormal chiasmatic projections found in albinism
A transgenic mouse model with inducible Tyrosinase gene expression using the tetracycline (Tet-on) system allows regulated rescue of abnormal chiasmatic projections found in albinism
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DOI：
10.1111/j.1600-0749.2004.00158.x
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发表时间：
2004-08-01
期刊：
影响因子：
--
通讯作者：
Montoliu, L
中科院分区：
文献类型：
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作者：
Giménez, E;Lavado, A;Montoliu, L
视网膜色素沉着的先天性缺陷，如I型眼皮肤白化病（OCA1），酪氨酸酶缺陷，导致影响视网膜和进入大脑的视觉异常。在白化病遗传背景下表达功能性酪氨酸酶基因的转基因动物显示出所有这些异常的纠正，暗示酪氨酸酶在正常视网膜发育中的功能作用。为了解决酪氨酸酶在哺乳动物视觉系统发育中的作用，我们利用四环素（TET-ON）系统建立了酪氨酸酶基因诱导表达的转基因小鼠模型。我们培育了两种类型的转基因小鼠：一种是在小鼠酪氨酸酶启动子及其基因座控制区（LCR）的控制下表达反激活子rtTA嵌合蛋白的小鼠；第二，转基因小鼠在强力霉素存在下表达由rtTA诱导的最小启动子驱动的小鼠酪氨酸酶cDNA结构。选择双转基因小鼠系进行了诱导实验。从胚胎发育早期诱导酪氨酸酶的表达，并用组织学和生化方法对杂合和纯合双转基因个体的酪氨酸酶表达影响进行了评价。我们发现，与对照组相比，被诱导的动物眼睛中的酪氨酸酶活性有所增加。然而，在类似的实验中，该基因的激活存在显著的可变性。尽管如此，我们可以观察到，在白化病中，从第一个妊娠周开始诱导的动物中，未交叉的交叉通路被纠正了。这些小鼠可能有助于揭示酪氨酸酶在哺乳动物视觉发育中的作用。
Congenital defects in retinal pigmentation, as in oculocutaneous albinism Type I (OCA1), where tyrosinase is defective, result in visual abnormalities affecting the retina and pathways into the brain. Transgenic animals expressing a functional tyrosinase gene on an albino genetic background display a correction of all these abnormalities, implicating a functional role for tyrosinase in normal retinal development. To address the function of tyrosinase in the development of the mammalian visual system, we have generated a transgenic mouse model with inducible expression of the tyrosinase gene using the tetracycline (TET-ON) system. We have produced two types of transgenic mice: first, mice expressing the transactivator rtTA chimeric protein under the control of mouse tyrosinase promoter and its locus control region (LCR), and; second, transgenic mice expressing a mouse tyrosinase cDNA construct driven by a minimal promoter inducible by rtTA in the presence of doxycycline. Inducible experiments have been carried out with selected double transgenic mouse lines. Tyrosinase expression has been induced from early embryo development and its impact assessed with histological and biochemical methods in heterozygous and homozygous double transgenic individuals. We have found an increase of tyrosinase activity in the eyes of induced animals, compared with littermate controls. However, there was significant variability in the activation of this gene, as reported in analogous experiments. In spite of this, we could observe corrected uncrossed chiasmatic pathways, decreased in albinism, in animals induced from their first gestational week. These mice could be instrumental in revealing the role of tyrosinase in mammalian visual development.