Collal Driven Ligand-Regulated Cre Transgenic Mice

描述（由申请人提供）：本补助金申请的目标是 产生和测试含有配体调节的Cre的转基因小鼠系 由大鼠Collal启动子的3.6和2.3kb片段驱动的重组酶。 目前可用的信息T2表明，他莫昔芬调节的Cre， Cre-ER，可能是最适合我们的研究，未修改的Cre 重组酶组成型催化loxP位点之间的DNA缺失， 然而，Cre-ER T2在不存在雌激素类似物的情况下是无活性的 他莫昔芬。含有3.6和2.3 kb Col I al启动子的构建体 将产生驱动Cre-ER T22并用于产生转基因小鼠。 这些转基因小鼠品系的测试将通过杂交来进行 用ROSA 26 Cre报告小鼠品系，其中表达β-半乳糖苷酶 （β-gal）或绿色荧光蛋白（GFP）依赖于Cre活性。它 预期报告基因表达将特异于细胞类型 其表达Collal启动子，并且依赖于他莫昔芬的注射。我们 将描述他莫昔芬治疗的最小剂量和时间过程 需要最佳诱导报告基因。我们还将描述 以该剂量长期他莫昔芬治疗对骨代谢的影响。的 开发这些线的目的是使组织特异性和时间特异性 成骨细胞中表达的基因的受调节的失活， 被认为在调节成骨细胞功能中起重要作用，但其 在成年动物中的作用尚不清楚。通过允许一个 基因在早期发育和失活的基因在成年成骨细胞， 我们可以了解该基因在成人骨代谢中的特殊作用。

DESCRIPTION (provided by applicant): The goal of this grant application is to generate and test transgenic mouse lines containing ligand regulated Cre recombinase driven by 3.6 and 2.3 kb fragments of the rat Collal promoter. Currently available information T2 indicates that a tamoxifen regulated Cre, Cre-ER , is probably the most appropriate for our studies, Unmodified Cre recombinase constitutively catalyzes deletion of DNA between loxP sites, however Cre-ER T2 is inactive in the absence of the estrogen analogue tamoxifen. Constructs containing the 3.6 and 2.3 kb Col I al promoter driving Cre-ER T22 will be produced and used to generate transgenic mice. Testing of these transgenic mouse lines will be carried out by crossing them with a ROSA 26 Cre reporter mouse strain in which expression of B-galactosidase (beta-gal) or green fluorescent protein (GFP) is dependent on Cre activity. It is expected that reporter gene expression will be specific to the cell types that express the Collal promoters, and dependent on injection of tamoxifen. We will characterize the minimum dosage and time course of tamoxifen treatment needed to optimally induce the reporter gene. We will also characterize the effects of long-term tamoxifen treatment at this dosage on bone metabolism. The purpose for developing these lines is to enable tissue specific and temporally regulated inactivation of genes that are expressed in osteoblasts and are believed to play important roles in regulating osteoblast function, but whose role in adult animals is not understood. By allowing normal expression of a gene during early development and inactivating the gene in adult osteoblasts, we can learn about the specific role of the gene in adult bone metabolism.