HERITABLE DISORDERS OF CONNECTIVE TISSUE

该科继续进行研究， 结缔组织遗传性疾病的机制，特别是 成骨诱导因子（OI）和Ehlers-Danlos（EDS）， 这些信息对这些疾病的治疗。 该科的一个持续兴趣是鉴定胶原蛋白， OI和EDS患者中的突变，并确定 突变的类型和位置与 结缔组织疾病α 2（I）胶原蛋白链突变 本节和其他实验室确定的其他实验提供了 支持我们提出的区域模式。 该科有三个主要项目。一个主要项目是 开发突变胶原等位基因的选择性反义抑制， 作为一种治疗干预的方法。今年我们转向了 使用反义锤头状核酶。在体外，我们已经证明 等位基因特异性切割并确定切割参数。我们 已经用总RNA和合成RNA进行了竞争实验， 目标的 我们现在正在寻找载体结构来确定抑制 在培养细胞中的稳定性和效率。 第二个主要项目是产生一个小鼠模型， 非致命性OI我们已经使用定点突变来产生一种 具有模拟非致死性人OI的点突变的构建体。的 cre-lox重组系统将用于控制 突变和lox-stop-lox构建体的表达已经被 在含有内含子的外显子之前引入内含子， 致病突变我们已经分离出重组ES细胞， 成功生成嵌合体。 我们一直在发展的第三个主要关注点是 骨生物学我们用培养的成骨细胞来研究 骨细胞修饰并分泌突变胶原。我们也在追求 OI基质的继发性非胶原异常和 OI成骨细胞对TGF-β刺激的反应。 在临床研究中，我们正在继续我们的治疗试验的增长 激素对发育不全矮小儿童生长影响 刺激、骨密度和骨形态测量特性。我们 继续我们在OI神经方面的合作兴趣 最大限度地发挥OI儿童的身体功能， 积极的康复

The Section has continued its studies aimed at elucidating the molecular mechanisms of heritable disorders of connective tissue, specifically osteogenesis imperfecta (OI) and Ehlers-Danlos (EDS), and at applying this information to the treatment of these disorders. One continuing interest of the Section is to identify the collagen mutations in patients with OI and EDS and determine the relationship between the type and location of the mutation and the severity of the connective tissue disorder. Mutations in the alpha2(I) collagen chain identified by this Section and other labs have provided additional support for the regional model we have proposed. There are three primary projects in the Section. One primary project is to develop selective antisense suppression of the mutant collagen allele as an approach for therapeutic intervention. This year we have turned to the use of antisense hammerhead ribozymes. In vitro, we have demonstrated allele- specific cleavage and determined the parameters for cleavage. We have conducted competition experiments with total RNA and synthetic targets. We are now pursuing vector constructs to determine suppression stability and efficiency in cultured cells. The second primary project is the generation of a murine model for non-lethal OI. We have used site-directed mutagenesis to produce a construct with a point mutation mimicking non-lethal human OI. The cre-lox recombination system will be used to control the timing of expression of the mutation and a lox-stop-lox construct has been introduced into the intron prior to the exon containing the disease-causing mutation. We have isolated recombinant ES cells and have successfully generated chimeras. A third major focus of interest which we have been developing is in the bone biology of OI. We are using cultured osteoblasts to study the way bone cells modify and secrete mutant collagen. We are also pursing the secondary non-collagenous abnormalities of OI matrix and the response of OI osteoblasts to TGF-beta stimulation. In clinical studies, we are continuing our treatment trial of growth hormone in short children with OI to determine its effects on growth stimulation, bone density and bone morphometric properties. We are continuing our collaborative interests in the neurological aspects of OI and in maximizing the physical functioning of OI children though aggressive rehabilitation.