胞质异质性——人类肿瘤组织线粒体基因突变的普遍现象

为了探讨不同肿瘤组织中线粒体基因体细胞性突变的胞质异质性和同质性状态,利用32对重叠引物对149例肿瘤组织和匹配的正常组织的全线粒体基因进行PCR扩增,并同时进行时相温度梯度凝胶电泳扫描突变筛选,基因测序确定突变类型与异质状况。结果表明,不同肿瘤组织中线粒体基因体细胞性突变的异质率不同,口腔癌（65%）和食道癌（64%）具有较高的异质率,其次为乳腺癌（45.9%）。4种转换形式的发生频率Hm→Hm > Hm→Ht > Ht→Hm > Ht→Ht。碱基转换的主要转换形式为Hm→Hm,碱基颠换则以Hm→Ht。认为胞质异质性是人类肿瘤组织线粒体基因突变的普遍现象。Abstract: To explore the status of heteroplasmy and homoplasmy of Mitochondrial DNA somatic mutations in different tumors. DNA from 149 tumors and corresponding normal tissues were extracted and entire mitochondrial genome was amplified using 32 pairs of overlapping primers. The somatic mutations were screened by temporal temperature gradient gel electrophoresis and their heteroplasmic statute were identified by sequencing. The results showed that the incidence rate of heteroplasmy of mitochondrial DNA somatic mutations varies in different tumors. There is a high rate of heteroplasmic mutation in oral cancer (65%) and esophageal cancer (64%), followed by breast cancer (45%). The frequency of four transfer types is Hm (homoplasmy)→Hm (heteroplasmy) > Hm→Ht > Ht→Hm > Ht→Ht. The main transfer forms of transition and transversion mutations are Hm→Hm and Hm→Ht respectively. Heteroplasmy is a common phenomenon in mitochondrial DNA somatic mutations of human tumors.     

重建邻接关系树评估原发性高血压患者的遗传性

探讨原发性高血压患者的遗传性,评估线粒体D环控制区基因变异在高血压发病中的作用。提取原发性高血压患者和正常血压人群DNA各20例,用3对交叉重叠引物扩增全部线粒体控制区D环基因,直接基因测序并重建邻接关系树,分析原发性高血压的基因变异特点。结果发现部分高血压病患者具有明显群聚倾向,与正常血压人群和其他无群聚倾向的高血压患者比较,存在高频率、高密度的D环控制区基因变化（P<0.01）,尤以np152T->C、np182C->T、np189A->G、np247G->A、np16187C->T、np16189T->C、np16264C->T、np16270C->T和np16311T->C等多态性变化显著,并因此造成np16184~16193微卫星区域多聚C长度改变。本研究提示部分高血压病患者有群聚现象,基因型np152C、np182T、np247A、np16187T、np16189C、np16264T、np16270T和np16311C可能是此聚类族高血压患者的易感遗传标记。Abstract：To explore the inheritable character in essential hypertension and to evaluate the role of mitochondrial DNA (mtDNA) variations of the D-loop region in the pathogenesis of hypertension, the entire genome of the D-loop region from the hypertensive and the normotensive (20 cases, each) was amplified using 3 pairs of overlapping primers and followed by sequencing. We reconstructed the Neighbor-Joining tree and analyzed the mtDNA variations in the D-loop region. The results exhibited that one clustering branch harbored some hypertensive, who had significantly higher frequency and density of mtDNA variations (both P<0.01), especially the polymorphisms of np152T->C, np182C->T, np189A->G, np247G->A, np16187C->T, np16189T->C, np16264C->T, np16270C->T and np16311T->C. This study suggested that there was an aggregative phenomenon in some hypertensive. The genotypes of np152C, np182T, np247A, np16187T, np16189C, np16264T, np16270T and np16311C may be potential genetic markers for susceptibility to hypertension.