Genetics of Sagg: A Heritable Mouse Model for Cutis Laxa

Sagg 遗传学：皮肤松弛的可遗传小鼠模型

• 批准号: 6662722
• 负责人: PAUL J CHRISTNER
• 金额: $ 11.78万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-20 至 2005-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6662722
• 关键词: collagen; cutis laxa; disease /disorder model; elastin; extracellular matrix; fibroblasts; gene mutation; genetic mapping; genetic markers; genetic recombination; genetically modified animals; in situ hybridization; laboratory mouse; messenger RNA; model design /development; molecular genetics; northern blottings; phenotype; skin

DESCRIPTION (provided by applicant): Cutis laxa is a connective tissue disease of the skin of unknown cause, characterized by sagging skin, premature wrinkling and reduced skin elasticity. It occurs in heritable and acquired forms. Although classically the disease only affects the skin it appears to occur in many variations or subsets affecting a variety of other organs in some patients. An animal model to study the molecular mechanisms of cutis laxa would be extremely useful. Recently, the existence of mice carrying the Sagg mutation was described (1). These mice were named Sagg because they have heritable saggy or loose skin that resembles characteristics of skin found in patients with cutis laxa. Associated with the loose skin is a profound reduction of collagen and elastin in the dermis. We propose this loose skin mutant mouse strain, named Sagg, as a model for the heritable form of cutis laxa. In this R21 application, we intend to refine the position of the Sagg mutation and to characterize the phenotype of this mutant mouse to determine whether it is a suitable model for cutis laxa. In Specific Alm I we will obtain Sagg N2 mice from an intersubspecific backcross of (1231-1/140Sagg/+ x CAST/ei)Fl x CAST/ci and construct a fine-map of the recombination events between the molecular markers, DIMU232 and DIAM234. We will delimit the region in which Sagg resides to less than 2 cM, as a preliminary but necessary step for chromosome walking experiments aimed at locating and cloning the gene. In Specific Aim 2, we will characterize the phenotype of Saggl+ mice at monthly intervals from ages I to 12 months by performing histological and biochemical analyses on the skin, lungs, kidney, heart and aorta. These studies will include in situ hybridizations to determine the spatial and temporal expression of collagen types I and III and elastin mRNAs in these tissues. Dermal fibroblasts will be used for Northern blot analyses to examine the steady state mRNA levels of additional genes which will include: A; candidate genes which have been identified from the results of Specific Aim 1, and B; genes encoding extracellular matrix components (EMC) which might be expected to be affected by the Sagg mutation. These experiments will also include genes encoding enzymes involved in the degradation and removal of the EMC. These studies will be undertaken in order to elucidate the downstream molecular events resulting from the Sagg mutation.

描述（申请人提供）：皮肤松弛症是一种原因不明的皮肤结缔组织疾病，其特征是皮肤下垂、过早起皱纹和皮肤弹性降低。它以遗传和后天的形式出现。虽然传统上该疾病仅影响皮肤，但它似乎以许多变异或亚型发生，影响一些患者的各种其他器官。研究皮肤松弛分子机制的动物模型将非常有用。最近，描述了携带 Sagg 突变的小鼠的存在 (1)。这些小鼠被命名为“Sagg”，因为它们具有遗传性下垂或松弛的皮肤，类似于皮肤松弛患者的皮肤特征。与皮肤松弛相关的是真皮中胶原蛋白和弹性蛋白的大幅减少。我们提出这种皮肤松弛的突变小鼠品系，名为 Sagg，作为皮肤松弛的遗传形式的模型。在此 R21 应用中，我们打算细化 Sagg 突变的位置并表征该突变小鼠的表型，以确定其是否适合皮肤松弛模型。在具体Alm I中，我们将从(1231-1/140Sagg/+ x CAST/ei)Fl x CAST/ci的亚种间回交获得Sagg N2小鼠，并构建分子标记DIMU232和DIMU232之间重组事件的精细图谱。直径234。我们将把 Sagg 所在的区域划定为小于 2 cM，作为旨在定位和克隆该基因的染色体行走实验的初步但必要的步骤。在具体目标 2 中，我们将通过对皮肤、肺、肾、心脏和主动脉进行组织学和生化分析，来表征从 1 个月到 12 个月的 Saggl+ 小鼠的表型。这些研究将包括原位杂交，以确定 I 型和 III 型胶原蛋白以及弹性蛋白 mRNA 在这些组织中的空间和时间表达。真皮成纤维细胞将用于 Northern blot 分析，以检查其他基因的稳态 mRNA 水平，其中包括：A；从特定目标1和B的结果中鉴定出的候选基因；编码细胞外基质成分（EMC）的基因预计会受到 Sagg 突变的影响。这些实验还将包括编码参与 EMC 降解和去除的酶的基因。进行这些研究是为了阐明 Sagg 突变引起的下游分子事件。