TSK-2--NEW ANIMAL MODEL FOR SCLERODERMA

系统性硬化症是一种病因不明的严重疾病 以胶原蛋白和其他结缔组织的过度积累为特征 皮肤和内脏的组织成分。 的机制 造成这种积累的原因尚不清楚。 一个动物模型来研究 SSc的分子机制将非常有用。 我们一直 培育一种新的突变小鼠，称为紧皮2或Tsk-2小鼠。 这种小鼠似乎是SSc的一个很好的新模型。 初步 工作，我们已经表明，Tsk-2鼠标显示增加的厚度， 皮肤柔韧性下降。 组织学检查显示-明显 真皮增厚和真皮胶原过度积聚。 在 生物化学研究，我们发现胶原蛋白的合成增加了6倍， 在Tsk-2小鼠皮肤中。 当测量皮肤中的RNA水平时，I型 胶原转录物也显示在Tsk-2中显著升高， 老鼠. 这些初步结果表明，Tsk-2突变小鼠 似乎显示结缔组织异常， 存在于SSc患者的皮肤中。 随着发现了独特的 Tsk-2小鼠突变，我们现在有另一个小鼠模型显示连接 与SSc患者中发现的组织异常相似。 的事实 两个独特的基因突变（Tsk-1和Tsk-2）在不同的染色体上导致 影响结缔组织的相似表型和分子变化 非常重要 它为我们提供了第二条途径， 了解控制胶原基因表达的机制， 这大大增加了我们最终找到 更适合SSc的治疗。 在本申请中，我们建议 描述Tsk-2中存在的结缔组织异常 老鼠. 将对皮肤和内部进行组织学研究。 器官，并将结果与来自Tsk-1小鼠的结果进行比较。 重点将 将胶原合成调控的研究置于培养的 应用最新技术水平的生物化学方法和重组 DNA技术。 我们将确定Tsk-2小鼠的调节缺陷 通过瞬时定位I型前胶原基因的相关区域， 转染完整的和缺失的推定的调控序列， 启动子 由于Tsk-2基因在肿瘤发生中的可能重要性， 调节胶原基因的表达，我们将确定的位置， 并开始采用亚种间 回交研究和染色体步移。 预计该 从这些研究中获得的知识将直接关系到 对胶原过度沉积的发病机制的认识 SSc的特点，并将提供一个更合理的方法来开发 这种无法治愈的毁灭性疾病的可能治疗模式。

Systemic sclerosis (SSc) is a serious disease of unknown cause characterized by excessive accumulation of collagen and other connective tissue components in the skin and internal organs. The mechanisms responsible for such accumulation are not known. An animal model to study the molecular mechanisms of SSc would be extremely useful. We have been breeding a new mutant mouse known as the tight skin 2 or the Tsk-2 mouse. This mouse appears to be an excellent new model for SSc. In preliminary work, we have shown that the Tsk-2 mouse displays increased thickness and decreased pliability of the skin. Histologic examination shows-marked thickening of the dermis and excessive accumulation of dermal collagen. In biochemical studies, we found that collagen synthesis was increased 6 fold in Tsk-2 mouse skin. When RNA levels in skin were measured, type I collagen transcripts were also shown to be markedly elevated in the Tsk-2 mouse. These preliminary results demonstrate that the Tsk-2 mutant mouse appears to display connective tissue abnormalities which resemble those present in the skin of patients with SSc. With the discovery of the unique Tsk-2 mouse mutation, we now have another mouse model displaying connective tissue abnormalities similar to those found in SSc patients. The fact that two unique genetic mutations (Tsk-1 & Tsk-2) on separate chromosomes lead to similar phenotypic and molecular changes affecting the connective tissue is extremely important. It allows us a second avenue of approach to understanding the mechanisms controlling collagen gene expression at the molecular level and it greatly increases our chances of eventually finding more suitable treatment for SSc. In this application, we propose to characterize the connective tissue abnormalities present in the Tsk-2 mouse. Histopathologic studies will be performed on skin and internal organs and the results compared to those from Tsk-1 mice. Emphasis will be placed o the study of regulation of collagen synthesis in cultured fibroblasts applying state of the art biochemical methods and recombinant DNA techniques. We will identify the regulatory defect in the Tsk-2 mouse by mapping pertinent regions of the type I procollagen gene by transient transfections of intact and deleted putative regulatory sequences of the promoter. Because of the likely importance of the Tsk-2 gene in the regulation of collagen gene expression, we will identify the location of and begin the process of cloning the Tsk-2 gene employing intersubspecific backcross studies and chromosome walking. It is expected that the knowledge gained from these studies will bee of direct relevance to the understanding of the pathogenesis of the excessive collagen deposition characteristic of SSc and will provide a more rational approach to develop possible modes of therapy for this incurable and devastating disease.