Harada F, Kimura A, Iwanaga T, Shimozawa K, Yata J, Sasazuki T
Department of Genetics, Kyushu University, Fukuoka, Japan.
Proc Natl Acad Sci U S A. 1987 Nov;84(22):8091-4. doi: 10.1073/pnas.84.22.8091.
Genomic DNAs from twelve Japanese patients with steroid 21-hydroxylase [21-OHase; steroid 21-monooxygenase; steroid, hydrogen-donor:oxygen oxidoreductase (21-hydroxylating); EC 1.14.99.10] deficiency were analyzed by Southern blot hybridization. A 3.7-kilobase (kb) Taq I and a 1.7-kb Pvu II restriction endonuclease fragment that correspond to a 21-OHase B gene were absent from the DNA of two unrelated patients with the salt-wasting form of the disease. However, a 10.5-kb Bgl II fragment corresponding to the region encompassing the 21-OHase B gene was still present in these two patients. The genes encoding 21-OHase were cloned from one of these two patients, who was homozygous by descent for HLA-A26;B39;C4A3;C4B1;DR4. Restriction endonuclease mapping as well as partial nucleotide sequencing analysis revealed that the 21-OHase B gene of the patient has been converted to the pseudogene, 21-OHase A, as far as the critical 0.5-kb sequence was concerned. Thus, the defect was due to both chromosomes each carrying two copies of 21-OHase A pseudogene and lacking functional 21-OHase B gene.
采用Southern印迹杂交法对12例患有类固醇21 -羟化酶[21 - OHase；类固醇21 -单加氧酶；类固醇，氢供体：氧氧化还原酶（21 -羟化）；EC 1.14.99.10]缺乏症的日本患者的基因组DNA进行了分析。两名患失盐型该疾病的非亲缘关系患者的DNA中，不存在与21 - OHase B基因相对应的3.7千碱基（kb）的Taq I和1.7 kb的Pvu II限制性内切酶片段。然而，这两名患者中仍存在与包含21 - OHase B基因的区域相对应的10.5 kb Bgl II片段。从这两名患者中的一名克隆了编码21 - OHase的基因，该患者通过遗传是HLA - A26；B39；C4A3；C4B1；DR4的纯合子。限制性内切酶图谱分析以及部分核苷酸序列分析表明，就关键的0.5 kb序列而言，该患者的21 - OHase B基因已转化为假基因21 - OHase A。因此，缺陷是由于两条染色体各自携带两个21 - OHase A假基因拷贝且缺乏功能性21 - OHase B基因所致。
