MOLECULAR GENETICS OF BMP2 AND 4--FOP CANDIDATE GENES

骨骼的胚胎发生和再生是复杂的 依赖于成功诱导软骨内分泌的发育事件 成骨 然而，人们对骨骼的遗传控制知之甚少 诱导 最近已经克隆了七种骨形态发生基因的cDNA， 蛋白质（BMP 1 -7），其中六个（BMP 2 -7）是一个古老的， 高度保守的分子家族参与了 胚胎模式形成的调节。 两种蛋白质的表达 相关的重组克隆（BMP 2和4）具有诱导细胞凋亡的能力。 异位软骨内成骨的整个发育过程 在组织学上与在极端的 进行性骨化性纤维发育不良（FOP）。 FOP是 一种渐进性致残性结缔组织疾病，特征为 先天畸形的胚原基的脚趾和 软骨内成骨的时空诱导紊乱. 异位部位 为我们的长期目标提供焦点的两个相关假设是 提出：第一，人骨形成蛋白2的分子结构和功能， 4个基因将提供基本的洞察遗传调控， 人的软骨内骨诱导和模式形成;第二，BMP 2 和4是FOP的候选基因，并且FOP的分子结构是 这些基因的调控区域可能在患有 FOP。 为了解决这些假设，我们打算：1。分离基因组克隆， BMP 2和4的部分长度cDNA作为探针。 2.识别 BMP 2和BMP 4的转录起始位点，以确定RNA编码 这些基因的区域。 3.表征启动子和其他顺式- 通过DNA序列分析确定BMP 2和4的调控区。 4.定义 启动子/增强子表达中BMP 2和4的功能控制单元 分析系统 5.通过RFLP分析进行FOP DNA突变筛查 用于BMP 2和4基因中的添加、缺失或重排， 基因组探针（在1中获得）。 人类基因组的分子组织和调控分析 BMP 2和4基因将促进阐明基础的长期目标 正常和紊乱的骨诱导机制，以及设计 合理的分子诊断和治疗策略， 人类骨骼的发育障碍。

The embryogenesis and regeneration of the skeleton are complex developmental events dependent on the successful induction of endochondral osteogenesis. Little is known, however, about the genetic control of bone induction. cDNAs have recently been cloned for seven bone morphogenetic proteins (BMP1-7), six of which (BMP2-7) are members of an ancient and highly conserved family of molecules involved in the developmental regulation of embryonic pattern formation. Proteins expressed from two related recombinant clones (BMP2 & 4) possess the capacity to induce the entire developmental program of endochondral osteogenesis in an ectopic site in a pattern histologically identical to that seen in the extremely rare genetic disorder Fibrodysplasia Ossificans Progressiva (FOP). FOP is a progressively disabling connective tissue disorder characterized by congenital malformations of the blastemal anlage of the toes and disordered temporal and spatial induction of endochondral osteogenesis at ectopic sites. Two related hypotheses that provide the focus for our long-term goals are proposed: first, the molecular structure and function of the human BMP2 & 4 genes will provide fundamental insight into the genetic regulation of endochondral bone induction and pattern formation in humans; second, BMP2 & 4 are candidate genes for FOP, and the molecular structure of the regulatory control regions of these genes may be abnormal in patients with FOP. To address these hypotheses, we intend to: 1. Isolate genomic clones for BMP2 & 4 using partial length cDNAs as probes. 2. Identify the transcription initiation sites of BMP2 and BMP4 to define the RNA-coding regions of these genes. 3. Characterize the promoter and other cis- regulatory regions of BMP2 & 4 by DNA sequence analysis. 4. Define the functional control unit of BMP2 & 4 in a promoter/enhancer expression assay system. 5. Perform mutational screening of FOP DNA by RFLP analysis for additions, deletions, or rearrangements in BMP2 & 4 genes using genomic probes (obtained in 1). Analysis of the molecular organization and regulatory control of the human BMP2 & 4 genes will foster the long-term goals of elucidating basic mechanisms of normal and disordered bone induction, and of designing rational molecular diagnostic and treatment strategies for a wide range of developmental disorders of the skeleton in humans.