GENETIC ANALYSIS OF BONE MORPHOGENETIC PROTEINS

骨形态发生蛋白的遗传分析

• 批准号: 2081410
• 负责人: DAVID M KINGSLEY
• 金额: $ 32.62万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1997-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2081410
• 关键词: RNA directed DNA polymerase; alleles; biological signal transduction; bone development; bone fracture; bone regeneration; gene expression; gene mutation; genetic models; genetic regulatory element; histogenesis; immunoprecipitation; in situ hybridization; laboratory mouse; molecular cloning; musculoskeletal regeneration; northern blottings; nucleic acid probes; nucleic acid sequence; phenotype; polymerase chain reaction; protein structure function; skeletal disorder; transforming growth factors; western blottings

The long term goal of this research is to define the molecular mechanisms that control the growth and patterning of skeletal tissue. This is a general problem in the development of higher animals, and is of particular relevance to the diagnosis and treatment of human skeletal diseases and bone fractures. The studies are particularly directed to understanding the role of bone morphogenetic proteins (BMPs) in normal development. BMPs were originally isolated based on their ability to induce cartilage and bone formation when implanted under the skin of animals. Combinations of BMPs and a carrier matrix are sufficient to induce a complex cascade of chemotactic and differentiation events that ultimately results in the formation of a marrow filled bony ossicle at ectopic body sites. The presence of these proteins in mature bones, and their ability to stimulate new bone formation, suggests that they may be the natural mediators of bone growth and modeling during embryonic development and repair of bone fractures. Cloning studies have shown that most BMPs are members of a family of secreted signaling molecules that have structural homology to transforming growth factor beta. The BMPs are strikingly conserved in evolution, with close relatives present in organisms such as the fruit fly Drosophila. BMP-like proteins have thus existed for at least a half billion years, and must predate the evolutionary invention of bone and cartilage. Mutations in a Drosophila homolog of a BMP gene disrupt early dorsal/ventral patterning of the embryo and are lethal. These findings, together with data showing that mammalian BMPs are expressed in many different tissues during mouse development, suggest that the BMPs may play diverse roles in higher animals as well. Until recently, no mutations have been available to test the function of BMPs in vertebrates. However, this laboratory has recently shown that a BMP gene called Bmp-5 is defective in mice carrying mutations at the short ear locus. Complete loss of the gene is compatible with full viability and fertility of mice, but is associated with a specific syndrome of skeletal abnormalities including reduction of the external ear, loss of one pair of ribs, alterations in the size and shape of many bones, defects in repair of bone fractures, and a number of soft tissue abnormalities. This important mouse mutation provides the first genetic model for defining the roles of BMPs in the development of higher organisms. The proposed studies will determine how the expression pattern of Bmp-5 is related to the phenotypes seen in mutant mice, which domains of BMP molecules are most important for normal function, and what roles BMPs play outside the skeleton. Cis-acting sequences will be defined that control when and where the Bmp-5 osteoinductive signal is expressed during normal development. Finally, short ear mice will be used to test a new genetic approach for correcting skeletal defects using cloned BMP genes.

这项研究的长期目标是定义分子机制 控制骨骼组织的生长和模式。这是一个 高等动物发展中的一般问题，特别是 与人类骨骼疾病的诊断和治疗有关 骨断裂。这些研究特别针对理解 骨形态发生蛋白（BMP）在正常发育中的作用。 BMP 最初是根据诱导软骨的能力而隔离的 植入动物皮肤下的骨形成。组合 BMP和载体矩阵足以诱导复杂的级联 趋化和分化事件最终导致 在异位身体部位形成骨髓填充的骨骨。这 这些蛋白质在成熟的骨骼中的存在及其刺激的能力 新的骨形成，表明它们可能是 骨骼发育和骨骼修复期间的骨骼生长和建模 断裂。克隆研究表明，大多数BMP是 具有结构同源性的分泌信号分子家族 改变生长因子β。 BMP在 进化，诸如果蝇之类的生物中存在近亲 果蝇。因此，BMP样蛋白至少存在一半 十亿年，必须早于骨骼的进化发明 软骨。 BMP基因的果蝇同源物中的突变早期破坏 胚胎的背或腹侧图案是致命的。这些发现， 以及显示哺乳动物BMP在许多人中表达的数据 在小鼠发育过程中，不同的组织表明BMP可以发挥作用 在上等动物中也有多种作用。直到最近，没有突变 可用于测试脊椎动物中BMP的功能。但是，这个 实验室最近表明，一个称为BMP-5的BMP基因在 携带突变的小鼠在短耳朵基因座上。完全丢失基因 与小鼠的完全生存能力和生育能力兼容，但与众不同 特定的骨骼异常综合征，包括减少 外耳，一双肋骨的损失，大小的改变和 许多骨骼的形状，骨折修复的缺陷和许多 软组织异常。这种重要的小鼠突变提供了 定义BMP在开发中的作用的第一个遗传模型 更高的生物。拟议的研究将决定表达方式 BMP-5的模式与突变小鼠中看到的表型有关，该表型 BMP分子的域对于正常功能最重要，什么 角色BMP在骨架外扮演。将定义顺式作用序列 该控制何时何地表达BMP-5骨诱导信号 在正常发展期间。最后，短耳老鼠将用于测试 使用克隆的BMP纠正骨骼缺陷的新遗传方法 基因。