文章编号:100025404(2002)0120055203论著RHO基因突变在视网膜色素变性中的分子遗传学分析张晓莉,府伟灵,薛强,张雪(第三军医大学附属西南医院检验科,重庆400038)提要:目的探明我国RP患者视紫红质(rhodopsin,RHO)基因突变的特征和意义。方法在98例RP患者中运用构象敏感凝胶电泳(conformationsensitivegelelectrophoresis,CSGE)和DNA直接测序方法检测RHO基因全编码区范围内的点突变。结果一个ADRP家系的4名患者第347密码子发生点突变,Pro347Leu;另一个ADRP家系中一名晚发型患者及其目前还未出现症状的女儿在第327密码子出现点突变,Pro327(12bpdel),而对照组100例健康成年人未发现上述两种突变。此外在1名患者和2名对照者中还检出一非致病的点突变,Ala299Ser,属单个碱基多态现象(singlenucleotidepolymophism,SNP)。结论98例RP先证者中检出2例携带RHO基因突变,由此可初步预测RHO基因在我国RP患者中的突变频率约为2%(95%的可信区间为0.2%～7.0%)。Pro347Leu突变改变了视蛋白C末端一段高度保守的氨基酸序列,致使该蛋白在胞内的运输发生障碍。Pro327(12bpdel)使突变蛋白的羧基末端失去了原有的磷酸化位点及上述一段高度保守的功能区,其可能的致病机制有待在今后的研究中通过建立相应的转基因模型或细胞培养系统来阐明。关键词:视网膜色素变性;视紫红质基因;基因突变;构象敏感凝胶电泳;DNA测序中图法分类号:R394.3;R774.13文献标识码:AMolecularstudyonrhodopsingenepointmutationsinretinitispigmentosaZHANGXiao2li,FUWei2ling,XUEQiang,ZHANGXue(DepartmentofClinicalLaboratories,SouthwestHospital,ThirdMilitaryMedicalUniversity,Chongqing400038,China)Abstract:ObjectiveToevaluatethepatternsandsignificanceofrhodopsin(RHO)genemutationsinChinesepatientswithretinitispigmentosa(RP).MethodsConformationsensitivegelelectrophoresis(CSGE)anddirectDNAsequencingwereemployedtodetectpointmutationsoccurringinthe5codingexonsandsplicesitesofrhodopsingenein98subjectedpatientswithRP.ResultsFourpatientsofoneautosomaldominantRP(ADRP)familywerefoundtohaveamissensemutationatcodon347,Pro347Leu.Onelate2onsetRPpatientandherdaughter,whohadnoclinicalexpressionsatpresent,werediscoveredtohaveanovelframeshiftmutationatcodon327,Pro327withonlyonebaseloss.Noneofthe2mutationswasfoundin100normalcontrols.Ala299Serwasfoundinonepatientasmissensemutation.TwocontrolsubjectsalsohadAla299Ser,suggestingitsnonpathogenicityandjustsinglenucleotidepolymophism(SNP).ConclusionSince2outof98RPpatientshaverhodopsinmutations,thefrequen2cyofRHOmutationsinRPmightbeabout2.0%(95%confidenceinterval0.2%～7.0%).AhighlyconservedC2terminalsequenceQVS(A)PAisalteredduetoPro347Leuandtherebyrhodopsinismisdirectedtoanincorrectsubcellularlocation.LossofallphosphorylationsitesattheC2termi2nusandthehighlyconservedsequenceQVS(A)PAmayoccurbecauseofPro327.Toelucidatethepredominantbiochemicaldefectsinsuchmutant,thestudyoftransgenicmiceandtransfectedculturecellscarryingPro327(12bpdel)isofgreatvalue.Keywords:retinitispigmentosa;rhodopsin;mutation;conformationsensitivegelelectrophoresis;sequencing视网膜色素变性(Retinitispigmentosa,RP)是视网膜感光细胞和色素上皮细胞变性导致夜盲和进行性视野缺损的一组最常见的致盲眼底病,全世界约有150万人患此病,其中中国人占1Π4左右[1]。RP同时又是具有遗传异质性的单基因遗传病,目前已证实的人类RP遗传位点已多达50多个,其中视紫红质(Rhodop2sin,RHO)基因由于其编码的蛋白仅在视杆细胞中专一性表达,并且基因也定位于常染色体显性遗传RP(AutosomaldominantRP,ADRP)的一遗传位点3q21224,从而成为了RP分子缺陷研究的第一个候选基因。突变研究至今已证实RHO基因突变可导致RP,并且可能是目前RP最常见的病因[2]。为明确RHO基因在我作者简介:张晓莉(1972-),女,上海市人,博士研究生,主治医...
