CAJ | 학술논문

目的在江苏淮阴一母系遗传非综合征型耳聋大家系中,寻找线粒体基因组上可能影响1555(A→G)突变表型的其他位点突变. 方法采用聚合酶链反应-限制性片段长度多态性分析 (PCR-restriction fragment length polymorphism, PCR-RFLP) 和测序技术,检测了核心分支家系中27名母系成员的线粒体DNA上1555位点和7445位点的碱基变化,进而对该家系2名母系成员的线粒体全基因组和其他25名母系成员线粒体12S rRNA基因 MTRNR1和tRNA-Ser(UCN)基因 MTTS1进行了全长测序. 结果再次证明了1555(A→G)突变是该家系成员致聋的分子生物学基础之一;并发现该家系27名母系成员的线粒体基因组中除1555(A→G)突变外,还同时存在有955-960(insC)同质型突变,两突变共分离.另外,新发现一个线粒体DNA突变--7449(insG),但该突变仅在2名母系成员中存在. 结论推测955-960(insC)突变可能通过改变12S rRNA基因的高级结构,并与1555(A→G)突变协同作用,提高了突变携带者对氨基糖甙类药物的敏感性;同时该突变可能也会导致线粒体蛋白质的合成缺陷,从而提高1555(A→G)突变致聋的外显率.
목적재강소회음일모계유전비종합정형이롱대가계중,심조선립체기인조상가능영향1555(A→G)돌변표형적기타위점돌변. 방법채용취합매련반응-한제성편단장도다태성분석 (PCR-restriction fragment length polymorphism, PCR-RFLP) 화측서기술,검측료핵심분지가계중27명모계성원적선립체DNA상1555위점화7445위점적감기변화,진이대해가계2명모계성원적선립체전기인조화기타25명모계성원선립체12S rRNA기인 MTRNR1화tRNA-Ser(UCN)기인 MTTS1진행료전장측서. 결과재차증명료1555(A→G)돌변시해가계성원치롱적분자생물학기출지일;병발현해가계27명모계성원적선립체기인조중제1555(A→G)돌변외,환동시존재유955-960(insC)동질형돌변,량돌변공분리.령외,신발현일개선립체DNA돌변--7449(insG),단해돌변부재2명모계성원중존재. 결론추측955-960(insC)돌변가능통과개변12S rRNA기인적고급결구,병여1555(A→G)돌변협동작용,제고료돌변휴대자대안기당대류약물적민감성;동시해돌변가능야회도치선립체단백질적합성결함,종이제고1555(A→G)돌변치롱적외현솔.
Objective To ascertain whether other variations coexist with 1555(A→G) mutation in the mitochondrial DNA and may aggravate the severity of hearing loss or increase the penetrance of 1555(A→G) mutation in a large family with maternally inherited nonsyndromic deafness in Huaiyin, Jiangsu province. Methods PCR-restriction fragment length polymorphism (PCR-RFLP) was used to screen both the nt1555 and the nt7445 of the mitochondrial DNA from 27 maternal members in the core family; and then the mitochondrial genomes from two maternal members, and the 12S rRNA genes MTRNR1 and tRNA-Ser(UCN) gene MTTS1 from the others, were amplified by PCR-RFLP and were sequenced. Results 1555(A→G) mutation in the mitochondrial DNA was reverified to be one of the major factors which cause maternally inherited nonsyndromic deafness and the cosegregation of 955-960(insC) and 1555(A→G) was present in this family. Moreover,7449 (insG), a novel homoplasmic mutation in the tRNA-Ser(UCN) gene, was found to co-exist with 1555(A→G) mutation in two maternal members. Conclusion The cosegregation of 955-960(insC) and 1555(A→G) implies that 955-960(insC) may synergistically cause hearing loss in the presence of an 1555(A→G) mutation,serving as an aggravating factor to enhance the sensitivity to aminoglycosides, and may sometimes increase the penetrance of 1555(A→G) mutation.