Molecular basis for the progeroid variant of Ehlers-Danlos syndrome - Identification and characterization of two mutations in galactosyltransferase I gene
Molecular basis for the progeroid variant of Ehlers-Danlos syndrome - Identification and characterization of two mutations in galactosyltransferase I gene
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DOI：
10.1074/jbc.274.41.28841
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发表时间：
1999-10-08
影响因子：
4.8
通讯作者：
Furukawa, K
中科院分区：
文献类型：
--
作者：
Okajima, T;Fukumoto, S;Furukawa, K
半乳糖基转移酶I(EC 2.4.1.133)参与了蛋白多糖共同连接区的合成，已有报道由半乳糖基转移酶I(EC2.4.1.133)缺陷引起。最近，我们克隆了半乳糖基转移酶I(XGalT-1)的cDNA(Okajima，T.，Yoshida，K.，Rondo，T.和Furukawa，H，(1999)J.Biol)。化学。22915-22918)，因此，我们用逆转录聚合酶链式反应和直接测序的方法分析了一例早孕型E-D综合征患者的该基因突变。分别在186和206处检测到G和T到A和C的两个变化，然后我们测定了包含A186D和L206P突变的基因组DNA序列，显示未受影响的父母和两个兄弟姐妹是两个不同突变之一的杂合子和正常，而患者都有两个不同的突变基因。对含有单个突变的XGalT-1克隆的酶活性进行了检测，结果表明，L206P克隆完全失去了活性，而A186D则分别保持了50%和10%的活性，分别与转基因细胞提取物和重组可溶性酶的活性相近。此外，L206P酶在转基因细胞胞浆内呈弥漫性染色，而野生型或A186D克隆细胞则呈高尔基体染色。提示XGalT-1基因突变至少是早孕型E-D综合征的主要分子基础之一。
Progeroid type Ehlers-Danlos (E-D) syndrome was reported to be caused by defects in galactosyltransferase I (EC 2.4.1.133), which is involved in the synthesis of common linkage regions of proteoglycans. Recently, we isolated cDNA of the galactosyltransferase I (XGalT-1) (Okajima, T., Yoshida, K., Rondo, T., and Furukawa, H, (1999) J. Biol. Chem. 274, 22915-22918), Therefore, we analyzed mutations in this gene of a patient with progeroid type E-D syndrome by reverse transcription polymerase chain reaction and direct sequencing. Two changes of G and T to A and C at 186 and 206, respectively, were detected, Then, we determined the genomic DNA sequences encompassing the A186D and L206P mutations, revealing that the unaffected parents and two siblings were heterozygous for either one of the two different mutations and normal, while the patient had both of two different mutant genes. Enzymatic functions of cDNA clones of XGalT-1 containing the individual mutations were examined, elucidating that L206P clone completely lost the activity, while A186D retained similar to 50% or 10% of the activity when analyzed with extracts from cDNA transfectant cells or recombinant soluble enzymes, respectively. Moreover, L206P enzyme showed diffuse staining in the cytoplasm of transfectant cells, while the wild type or A186D clones showed Golgi pattern. These results indicated that the mutations in XGalT-1 were at least one of main molecular basis for progeroid type E-D syndrome.