Collal Driven Ligand-Regulated Cre Transgenic Mice

描述(由申请者提供)：本次拨款申请的目标是 构建和检测含配体调控Cre基因的转基因小鼠 大鼠胶原启动子3.6 kb和2.3 kb片段驱动的重组酶。 当前可用的信息T2表明他莫昔芬调节的Cre， Cre-ER，可能是最适合我们研究的，未经修饰的Cre 重组酶结构性地催化loxP位点之间的DNA缺失， 然而，在没有雌激素类似物的情况下，Cre-ER T2是无效的 他莫昔芬。含有3.6 kb和2.3 kb基因启动子的重组载体 将生产驱动Cre-ER T22并用于产生转基因小鼠。 对这些转基因小鼠品系的测试将通过杂交进行。 用表达B-半乳糖苷酶的ROSA 26 Cre报告小鼠品系 (β-半乳糖)或绿色荧光蛋白(GFP)取决于Cre活性。它 预计报告基因的表达将针对细胞类型 表达胶原启动子，并依赖于他莫昔芬的注射。我们 将描述三苯氧胺治疗的最小剂量和时间进程 需要以最佳方式诱导报告基因。我们还将描述 长期服用该剂量三苯氧胺对骨代谢的影响。这个 开发这些品系的目的是使组织特异性和临时性 在成骨细胞中表达的基因的受控失活 据信在调节成骨细胞功能方面起着重要作用，但其 在成年动物中的作用还不清楚。通过允许正常表达 基因在成人成骨细胞早期发育和失活， 我们可以了解该基因在成人骨骼代谢中的具体作用。

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.