Mutation in the COL2A1 gene in a patient with hypochondrogenesis. Expression of mutated COL2A1 gene is accompanied by expression of genes for type I procollagen in chondrocytes.
Mutation in the COL2A1 gene in a patient with hypochondrogenesis. Expression of mutated COL2A1 gene is accompanied by expression of genes for type I procollagen in chondrocytes.
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DOI：
10.1016/s0021-9258(17)36881-3
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发表时间：
1994-05
期刊：
影响因子：
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通讯作者：
P. Freisinger;L. Ala‐kokko;D. Leguellec;S. Franc;R. Bouvier;P. Ritvaniemi;D. Prockop;J. Bonaventure
中科院分区：
文献类型：
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作者：
P. Freisinger;L. Ala‐kokko;D. Leguellec;S. Franc;R. Bouvier;P. Ritvaniemi;D. Prockop;J. Bonaventure
一个新的显性突变的COL 2A 1基因被发现在一个38周大的胎儿与软骨发育不良。变性梯度凝胶电泳分析编码COL 2A 1基因三螺旋结构域的所有44个外显子及其相应的外显子-内含子边界。该技术检测到外显子35中的新序列变异。外显子35的测序显示了一个单碱基突变，该突变将位置604处的甘氨酸密码子转换为丙氨酸密码子。从患病软骨中提取的胃蛋白酶消化的胶原蛋白的电泳显示II型胶原蛋白的α 1（II）链的双重带和I型胶原蛋白的α 1（I）和α 2（I）链的存在。二维分析溴化氰肽从II型胶原蛋白显示翻译后过度修饰的肽CB 12，CB 11，CB 8和CB10.5，而肽CB9.7迁移正常。软骨的显微镜检查显示，突变改变了生长板的组织。此外，关节软骨细胞含有大池的粗面内质网。细胞外基质的密度降低，并且II型胶原抗体染色的强度减弱。相反，观察到I型胶原抗体的显著染色。cRNA探针原位杂交显示患者软骨细胞的细胞质中有显著水平的α 1（I）mRNA。α 1（II）mRNA的信号与对照样品中的信号大致相同。因此，结果表明，I型和II型前胶原的基因在患者的软骨细胞中同时表达。
A new dominant mutation in the COL2A1 gene was found in a 38-week-old fetus with hypochondrogenesis. Denaturing gradient gel electrophoresis was used to analyze all 44 exons coding for the triple-helical domain of COL2A1 gene and the corresponding exon-intron boundaries. The technique detected a new sequence variation in exon 35. Sequencing of exon 35 demonstrated a single base mutation that converted the codon for glycine at position 604 to a codon for alanine. Electrophoresis of pepsin-digested collagen extracted from the diseased cartilage showed a doublet band of the alpha 1(II) chain of type II collagen and the presence of alpha 1(I) and alpha 2(I) chains of type I collagen. Two-dimensional analysis of cyanogen bromide peptides from the type II collagen revealed post-translational overmodification of peptides CB12, CB11, CB8, and CB10.5, whereas peptide CB9.7 migrated normally. Microscopic examination of cartilage showed that the mutation altered the organization of the growth plate. Also, articular chondrocytes contained large cisternae of rough endoplasmic reticulum. The density of the extracellular matrix was reduced, and the intensity of the staining with an antibody to type II collagen was diminished. In contrast, a significant staining with an antibody to type I collagen was observed. In situ hybridization with cRNA probes revealed a significant level of alpha 1(I) mRNA in the cytoplasm of the patient's chondrocytes. The signal for alpha 1(II) mRNA was about the same in control samples. The results indicated, therefore, that the genes for both type I and type II procollagens were simultaneously expressed in chondrocytes from the patient.