A Recessive Skeletal Dysplasia, SEMD Aggrecan Type, Results from a Missense Mutation Affecting the C-Type Lectin Domain of Aggrecan
A Recessive Skeletal Dysplasia, SEMD Aggrecan Type, Results from a Missense Mutation Affecting the C-Type Lectin Domain of Aggrecan
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DOI：
10.1016/j.ajhg.2008.12.001
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发表时间：
2009-01-09
影响因子：
9.8
通讯作者：
Krakow, Deborah
中科院分区：
文献类型：
--
作者：
Tompson, Stuart W.;Merriman, Barry;Krakow, Deborah
对一个有三个受影响后代的核心家庭的分析确定了一种常染色体隐性形式的脊柱干骺端发育不良，其特征是严重的身材矮小和独特的影像学表现。两个受影响的个体之间通过血统相同的单倍型的纯合性在15号染色体上的17.4 Mb间隔内确定了疾病基因的位点，该区域包含296个基因。这些基因进行了评估和排名的软骨选择性与全基因组微阵列数据，揭示只有两个基因，编码聚集蛋白聚糖和硫酸软骨素蛋白聚糖4，选择性地在软骨中表达。对来自受影响个体的聚集蛋白聚糖互补DNA的序列分析揭示了错义突变（c.6799G -> A）的纯合性，该错义突变预测聚集蛋白聚糖的G3结构域内的C型凝集素结构域中的p.D2267N氨基酸取代。预测D2267残基与钙离子结合，钙离子影响C型凝集素结构域的构象结合环，C型凝集素结构域介导与生腱蛋白和其他细胞外基质蛋白的相互作用。正常和突变G3结构域在哺乳动物细胞中的表达表明，突变产生了一个功能性的N-糖基化位点，但没有不利影响蛋白质的运输和分泌。表面等离子体共振研究表明，突变影响聚集蛋白聚糖G3结构域和腱生蛋白-C之间的相互作用的结合和动力学。这些发现确定了一个常染色体隐性骨骼发育不良和一个显着的作用，聚集蛋白聚糖C型凝集素域在调节软骨内骨化，从而，身高。
Analysis of a nuclear family with three affected offspring identified an autosomal-recessive form of spondyloepimetaphyseal dysplasia characterized by severe short stature and a unique constellation of radiographic findings. Homozygosity for a haplotype that was identical by descent between two of the affected individuals identified a locus for the disease gene within a 17.4 Mb interval on chromosome 15, a region containing 296 genes. These genes were assessed and ranked by cartilage selectivity with whole-genome microarray data, revealing only two genes, encoding aggrecan and chondroitin sulfate proteoglycan 4, that were selectively expressed in cartilage. Sequence analysis of aggrecan complementary DNA from an affected individual revealed homozygosity for a missense mutation (c.6799G -> A) that predicts a p.D2267N amino acid substitution in the C-type lectin domain within the G3 domain of aggrecan. The D2267 residue is predicted to coordinate binding of a calcium ion, which influences the conformational binding loops of the C-type lectin domain that mediate interactions with tenascins and other extracellular-matrix proteins. Expression of the normal and mutant G3 domains in mammalian cells showed that the mutation created a functional N-glycosylation site but did not adversely affect protein trafficking and secretion. Surface-plasmon-resonance studies showed that the mutation influenced the binding and kinetics of the interactions between the aggrecan G3 domain and tenascin-C. These findings identify an autosomal-recessive skeletal dysplasia and a significant role for the aggrecan C-type lectin domain in regulating endochondral ossification and, thereby, height.