臺灣一個第一型黏多醣儲積症（MPS I）患者致病基因的分子遺傳學研究

Molecular Genetic Analysis of α-L-Iduronidase Gene in a Chinese MPS I Patient

秦義雯(Yi-Wen Chin) ； 李桂楨(Guey-Jen Lee-Chen) ； 林炫沛(Shuan-Pei Lin)

《師大生物學報》 33卷1期 (1998/06) Pp. 37-45

https://doi.org/10.29812/BBNTNU.199806.0004

摘要

本研究的目的在探討台灣一位MPS I患者（766）的致病成因。首先利用聚合酶鏈反應，單股核酸構形多型性（PCR-SSCP）的技術，初步篩選可能帶有突變的IDUA基因表現子；其次針對SSCP構形異常的表現子加以選殖、定序分析。結果發現患者766的IDUA基因第619個胺基酸密碼發生CGA→GGA的改變，即由鹼性精胺酸Arg變成中性甘胺酸Gly（R619G）。利用對偶基因專一性的寡核苷酸引子（ASO）及藉由mismatch primer引入BsiWI限制酵素切割點的限制片段長度多型性（RFLP）分析，來檢視患者及其雙親的基因突變。結果發現患者為R619G的同型合子，而患者的父母親則皆為此突變的攜帶者。進一步構築了含R619G突變點的IDUA cDNA基因，經lipofection的方式轉移至COS-7細胞中表現後，含R619G變異的IDUA基因所表現的酵素活性，低於野生型的IDUA基因的1%。北方吸漬法（northern blot）分析重組基因轉移細胞株的mRNA表現量，顯示R619G的變異並未影響IDUA mRNA的穩定性，故推測R619G可能影響IDUA蛋白質的穩定性或IDUA酵素的活性。

關鍵字

第一型黏多醣儲積症 ； IDUA ； 基因突變

並列摘要

Molecular lesion of a Chinese patient (766) with mucopolysaccharidosis type I (MPS I) was investigated. The coding sequence and exon-intron borders of the α-L-iduronidase (IDUA) gene were amplified by polymerase chain reaction (PCR) and subjected to single strand conformation polymorphism (SSCP) analysis. The aberrant SSCP conformer was cloned and sequence determined. PCR-restriction fragment length polymorphism (RFLP) and allele specific oligonucleotide (ASO) based tests were developed to characterize the mutation. Patient 766 is homologous for mutation R619G (C to G transversion in codon 619). The mutation was inherited from both parents. Expression of R619G showed trace amounts of α-L-iduronidase activity compared to that of normal cDNA upon transfection into COS-7 cells. Conversely, a normal level of R619G mRNA was detected. R619G may affect the IDUA protein stability or its specific activity.

並列關鍵字

mucopolysaccharidosis type I ； α-L-iduronidase ； gene mutation