ARYLSULFATASE-A PSEUDODEFICIENCY - LOSS OF A POLYADENYLYLATION SIGNAL AND N-GLYCOSYLATION SITE
ARYLSULFATASE-A PSEUDODEFICIENCY - LOSS OF A POLYADENYLYLATION SIGNAL AND N-GLYCOSYLATION SITE
复制标题
DOI：
10.1073/pnas.86.23.9436
复制
发表时间：
1989-12-01
影响因子：
11.1
通讯作者：
VONFIGURA, K
中科院分区：
文献类型：
--
作者：
GIESELMANN, V;POLTEN, A;VONFIGURA, K
异色性脑白质营养不良是一种由芳基硫酸酯酶A缺乏引起的代谢紊乱，这种酶的缺乏在表面上健康的人中也被发现，这种情况下引入了假性缺乏一词。从1例AsA假缺陷等位基因纯合子中分离到芳基硫酸酯酶A(脑苷三硫酸酯水解酶；EC 3.1.6.8)(ASA)编码基因。序列分析显示有两个A.fwdarw。G跃迁。一种是将Arg-350改变为丝氨酸，导致失去一个已利用的N-糖基化位点。这种缺失解释了AsA假缺陷成纤维细胞中AsA体积较小的原因。将Ser-350引入正常的AsA基因并不影响AsA的合成速度、稳定性，也不影响稳定表达的幼鼠肾细胞中AsA的催化特性。因此，在AsA假性缺乏症中，N-连接的寡糖的丢失并不是导致AsA活性降低的原因。另一个是A·Fwdarw。G转换将终止密码子下游的第一个多聚腺苷化信号从AATAAC改变为AGTAAC。后者导致2.1千碱基(Kb)信使核糖核酸的严重缺乏。2.1kb RNA物种的缺乏为假缺陷成纤维细胞中AsA合成减少提供了解释。基因组DNA扩增和等位基因特异性寡核苷酸杂交在四个患有AsA假性缺乏症的无关个体中检测到这两种突变。
Metachromatic leukodystrophy is a metabolic disorder caused by the deficiency of arylsulfatase A. Deficiency of this enzyme is also found in apparently healthy individuals, a condition for which the term pseudodeficiency was introduced. The arylsulfatase A (cerebroside-3-sulfate 3-sulfohydrolase; EC 3.1.6.8) (ASA) encoding gene was isolated from an individual homozygous for the ASA pseudodeficiency allele. Sequence analysis revealed two A .fwdarw. G transitions. One changes Arg-350 to serine, which leads to the loss of a utilized N-glycosylation site. This loss explains the smaller size of ASA in ASA pseudodeficiency fibroblasts. The introduction of Ser-350 into normal ASA cDNA does not affect the rate of synthesis, the stability, or the catalytic properties of ASA in stably transfected baby hamster kidney cells. Therefore, the loss of the N-linked oligosaccharide does not contribute to the reduction of ASA activity in ASA pseudodeficiency. The other A .fwdarw. G transition changes the first polyadenylylation signal downstream of the stop codon from AATAAC to AGTAAC. The latter causes a severe deficiency of a 2.1-kilobase (kb) mRNA species. The deficiency of the 2.1-kb RNA species provides an explanation for the diminished synthesis of ASA seen in pseudodeficiency fibroblasts. Amplification of genomic DNA and hybridization with allele-specific oligonucleotides detected both mutations in four unrelated individuals with ASA pseudodeficiency.