Iida R, Yasuda T, Aoyama M, Tsubota E, Kobayashi M, Yuasa I, Matsuki T, Kishi K
Department of Forensic Medicine, Fukui Medical University, Japan.
Electrophoresis. 1997 Oct;18(11):1936-9. doi: 10.1002/elps.1150181108.
The fifth allele, DNASE15, of human deoxyribonuclease I (DNase I) has been discovered. Polymerase chain reaction fragments containing exon 5 of the DNase I gene were screened for DNA polymorphism using single-strand conformation polymorphism (SSCP) analysis. DNAs from 114 unrelated Japanese and 81 German individuals were tested and a new variant was detected. By DNA sequencing analysis, this variant was found to be caused by a heterozygous G-A transition at nucleotide position 1227 that results in a Val to Met substitution at amino acid position 92 of the mature enzyme. The nucleotide substitution was also confirmed by mismatched polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis. Genotyping of the variant could be carried out by three independent reactions based on PCR amplification, and phenotyping by isoelectric focusing followed by immunostaining. The results supported the presence of the fifth codominant allele, DNASE15, which generates a new isozyme.
人类脱氧核糖核酸酶I（DNase I）的第五个等位基因DNASE15已被发现。利用单链构象多态性（SSCP）分析，对包含DNase I基因第5外显子的聚合酶链反应片段进行DNA多态性筛查。对114名无关日本人和81名德国人个体的DNA进行检测，发现了一个新的变异体。通过DNA测序分析，发现该变异体是由核苷酸位置1227处的杂合G-A转换引起的，这导致成熟酶的第92位氨基酸处缬氨酸被甲硫氨酸取代。错配聚合酶链反应（PCR）-限制性片段长度多态性（RFLP）分析也证实了该核苷酸取代。该变异体的基因分型可通过基于PCR扩增的三个独立反应进行，表型分析则通过等电聚焦后免疫染色进行。结果支持第五个共显性等位基因DNASE15的存在，它产生一种新的同工酶。
