Muratani K, Hada T, Yamamoto Y, Kaneko T, Shigeto Y, Ohue T, Furuyama J, Higashino K
Third Department of Internal Medicine, Hyogo College of Medicine, Japan.
Proc Natl Acad Sci U S A. 1991 Dec 15;88(24):11315-9. doi: 10.1073/pnas.88.24.11315.
The human cholinesterase (ChE) gene from a patient with acholinesterasemia was cloned and analyzed. By using ChE cDNA as a probe, four independent clones were isolated from a genomic library constructed from the patient's DNA. Sequencing analysis of all of the four clones revealed that exon 2 of the ChE gene was disrupted by a 342-base-pair (bp) insertion of Alu element, including a poly(A) tract of 38 bp, which showed 93% sequence homology with a current type of human Alu consensus sequence. Southern blot analysis showed that the Alu insertion occurred in both alleles of the patient and was inherited in the patient's family. This Alu insertion was flanked by 15-bp of target site duplication in exon 2 corresponding to positions 1062-1076 of ChE cDNA, indicating that an Alu element could have been integrated by retrotransposition. Thus, this case provides an important clue to the mechanism of inactivation of a gene by integration of a retrotransposon.
对一名无胆碱酯酶血症患者的人胆碱酯酶（ChE）基因进行了克隆和分析。以ChE cDNA为探针，从该患者DNA构建的基因组文库中分离出4个独立克隆。对所有4个克隆的测序分析表明，ChE基因的外显子2被一个342碱基对（bp）的Alu元件插入破坏，其中包括一个38 bp的聚腺苷酸尾，该序列与当前人类Alu共有序列类型的序列同源性为93%。Southern印迹分析表明，Alu插入发生在患者的两个等位基因中，并在患者家族中遗传。该Alu插入两侧是外显子2中对应于ChE cDNA第1062 - 1076位的15 bp靶位点重复序列，表明Alu元件可能是通过逆转录转座整合的。因此，该病例为逆转座子整合导致基因失活的机制提供了重要线索。
