Galicka Anna, Wolczynski Slawomir, Lesniewicz Ryszard, Chyczewski Lech, Gindzienski Andrzej
Department of Medical Chemistry, Medical Academy of Białystok, Poland.
Acta Biochim Pol. 2002;49(2):443-50.
Cultured skin fibroblasts from a proband with a lethal form of osteogenesis imperfecta produce two forms of type I collagen chains, with normal and delayed electrophoretic migration; collagen of the proband's mother was normal. Peptide mapping experiments localized the structural defect in the proband to alpha1(I) CB8 peptide in which residues 123 to 402 are spaned. Direct sequencing of amplified cDNA covering this region revealed a G to A single base change in one allele of the alpha1(I) chain, that converted glycine 388 to arginine. Restriction enzyme digestion of the RT-PCR product was consistent with a heterozygous COL1A1 mutation. The novel mutation conforms to the linear gradient of clinical severity for the alpha1(I) chain and results in reduced thermal stability by 3 degrees C and intracellular retention of abnormal molecules.
来自一名患有致死型成骨不全症先证者的培养皮肤成纤维细胞产生两种形式的I型胶原链，其电泳迁移正常和延迟；先证者母亲的胶原正常。肽图分析实验将先证者的结构缺陷定位到α1(I) CB8肽段，该肽段跨度为第123至402位残基。对覆盖该区域的扩增cDNA进行直接测序，发现α1(I)链的一个等位基因中有一个从G到A的单碱基变化，该变化将甘氨酸388转变为精氨酸。RT-PCR产物的限制性酶切与杂合性COL1A1突变一致。该新突变符合α1(I)链临床严重程度的线性梯度，导致热稳定性降低3摄氏度，并使异常分子在细胞内滞留。
