Genetic dissection of skeletal patterning

骨骼模式的基因解剖

• 批准号: 6958579
• 负责人: Claudia T Kappen
• 金额: $ 22.64万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6958579
• 关键词: animal breeding; biotechnology; developmental genetics; gene environment interaction; gene expression; gene interaction; gene mutation; genetic mapping; genetic markers; genetic strain; homeobox genes; in situ hybridization; laboratory mouse; morphology; osteogenesis; skeletal system; vertebrate embryology

DESCRIPTION (provided by applicant): The crucial role of homeobox genes in patterning of the vertebrate skeleton is well established. Much is known about the specificity and cooperation of particular Hox genes in defined skeletal regions, but despite more than 10 years of functional experiments in numerous laboratories, it is still unknown how Hox transcription factors actually control vertebral identity. The transcriptional targets in the developing skeleton also have not been identified, a major obstacle to a mechanistic understanding of Hox regulated pathways. Here, I propose a genetic approach to the identification of Hox-controlled pathways; a new direction in the field of skeletal patterning. The central hypothesis is that skeletal patterning-- as regulated by Hox genes--manifests as a quantitative trait, which is controlled by gene-gene and gene-environment interactions. This proposition is supported by extensive data from our laboratory that demonstrate the existence of nutritional and genetic modifiers of Hox gene function in the skeleton. We have shown that (i) genetic factors modulate severity of skeletal anomalies in Hoxb6 knockout mice; (ii) phenotype manifestation is controlled by genetic background of the developing embryo itself; (iii) distinct skeletal elements are affected by region-specific pathways that operate largely independently; and that (iv) the number of genetic modifiers is small, and therefore experimentally tractable. Our major goal now is to define the genetic factors that interact with HoxbG in skeletal patterning by pursuit of the following Specific Aims: (1) to map the genomic location of the strain-specific genetic modifier(s) by microsatellite marker whole genome scan in a backcross of Hoxb6 mutants on C57BI/6 and 129Sv/Ev backgrounds; (2) to define the influence of genetic modifiers on manifestation of skeletal patterning phenotypes in Hoxb6 mutants by analyzing the mutation on the FVB genetic background; and (3) to characterize the expression of genes that are known mediators of skeletal patterning for their function in pathogenesis of Hoxb6 mutant phenotypes. The identification of modifier loci that act on skeletal patterning will reveal new molecular mechanisms in skeletal development and has important implications for the evolution of vertebrate body plans.

描述（由申请人提供）：同源盒基因在脊椎动物骨骼模式中的关键作用已得到充分证实。人们对特定骨骼区域中特定 Hox 基因的特异性和协作了解很多，但尽管在众多实验室进行了 10 多年的功能实验，但仍不清楚 Hox 转录因子实际上如何控制椎骨特性。发育中的骨架中的转录靶标也尚未确定，这是从机制上理解 Hox 调控途径的主要障碍。在这里，我提出了一种遗传方法来识别 Hox 控制的途径；骨骼图案领域的新方向。核心假设是，骨骼模式（受 Hox 基因调节）表现为数量性状，受基因-基因和基因-环境相互作用控制。这一主张得到了我们实验室的大量数据的支持，这些数据证明了骨骼中 Hox 基因功能的营养和遗传修饰剂的存在。我们已经证明，(i) 遗传因素调节 Hoxb6 敲除小鼠骨骼异常的严重程度； (ii) 表型表现受发育胚胎本身的遗传背景控制； (iii) 不同的骨骼元素受到很大程度上独立运作的区域特定途径的影响； (iv) 遗传修饰剂的数量很少，因此在实验上易于处理。我们现在的主要目标是通过追求以下具体目标来定义在骨骼模式中与 HoxbG 相互作用的遗传因素： (1) 通过微卫星标记全基因组扫描，在 C57BI/6 和 129Sv/Ev 背景上的 Hoxb6 突变体回交中绘制菌株特异性遗传修饰剂的基因组位置； (2) 通过分析FVB遗传背景上的突变，确定遗传修饰剂对Hoxb6突变体骨骼模式表型表现的影响；和 (3) 表征已知的骨骼模式介导基因的表达，这些基因在 Hoxb6 突变表型的发病机制中发挥作用。 作用于骨骼图案的修饰位点的鉴定将揭示骨骼发育中的新分子机制，并对脊椎动物身体结构的进化具有重要意义。