Targeted Overexpression of PTH-related Peptide

描述（由申请人提供）：PTHrP在20世纪80年代末被发现为恶性肿瘤体液性高钙血症综合征的介质，当时它是一种寻找功能的分子。PTHrP的一个功能是作为发育调节分子。最明确的这种作用是在软骨内骨形成、牙齿萌出和乳腺上皮形成中。在成人中，PTHrP作为机械诱导的产物在整个生物体的平滑肌结构中发挥作用。在过去的几年里，我们的小组一直专注于PTHrP在其他可兴奋细胞，我们在这里提出了四个项目，以进一步了解这些潜在的功能。其中两个项目（3和4）是全新的举措。 目的1是通过同源重组产生lacZ PTHrP敲入。该项目正处于囊胚注入阶段。该等位基因将在生理调节和条件性缺失实验中提供PTHrP基因读数。 目的2是建立模型，使PTHrP作为一种神经保护肽的潜在作用的研究。一个子目标是通过红藻氨酸受体驱动的Cre从海马的CA 3子区域有条件地删除PTHrP，第二子目标是通过诱导型钙调蛋白激酶驱动的Cre从CA 1子区域删除PTHrP。 Subaim 3是建立模型，使PTHrP参与神经元再生的研究，基于体外初步证据表明这样的功能。一个子目标将是删除PTHrP的肽能初级感觉神经元的背根神经节和第二删除PTHrP的表皮结构通过诱导的铬靶向系统。这些模型将分别集中在DRG和皮肤神经再生中的潜在PTHrP功能。 目的4将集中于PTHrP在体内机械调节骨形成中的潜在作用。这一目标也是基于体外这种效应的初步证据。待创建的模型将是在PR 1（RU-486）控制下的胶原基因驱动的Cre。

DESCRIPTION (provided by applicant): PTHrP was discovered in the late 1980s as the mediator of the syndrome of humoral hypercalcemia of malignancy, and it was at that time a molecule in search of a function. One PTHrP function is as a developmental regulatory molecule. The best defined such effects are in endochondral bone formation, the eruption of teeth, and formation of the mammary epithelium. In adults, PTHrP functions as a mechanically-induced product in smooth muscle structures throughout the organism. For the past several years, our group has focused on PTHrP in other excitable cells, and we propose here four projects to further our understanding of these potential functions. Two of these projects (3 and 4) are entirely new initiatives. Aim 1 is to create a lacZ PTHrP knock-in by homologous recombination. This project is at the blastocyst-injection stage. This allele will provide a PTHrP gene readout in physiological regulation and in conditional deletion experiments. Aim 2 is to create models that will enable study of the potential role of PTHrP as a neuroprotective peptide. One subaim will be to conditionally delete PTHrP from a CA3 subfield of the hippocampus via a kainite receptor-driven Cre and a second subaim to delete PTHrP from the CA1 subfield by an inducible calmodulin kinase-driven Cre. Subaim 3 is create models that will enable study of PTHrP involvement in neuronal regeneration, based on preliminary evidence in vitro that suggests such a function. One subaim will be to delete PTHrP in peptidergic primary sensory neurons of the dorsal root ganglia and a second to delete PTHrP in epidermal structures via an inducible Cre-targeting system. These models will focus on potential PTHrP functions in DRG and cutaneous nerve regeneration, respectively. Aim 4 will focus on the potential role of PTHrP in mechanical-regulated bone formation in vivo. This aim too is based on preliminary evidence of such an effect in vitro. The model to be created will be a collagen gene-driven Cre under the control of PR1 (RU-486).