用高保真DNA聚合酶介导的PCR检测β地中海贫血热点突变

目的用高保真DNA聚合酶介导的PCR检测β地中海贫血基因热点突变。方法选取已知中国人群β珠蛋白基因CD41-42、IVS-2nt654、TATAbox-28、CD17、CD71-72及CD26热点突变位点为检测靶点,分别设计3'末端与野生型基因位点或突变型基因位点完全配对的引物,并用硫化磷酸修饰,进行高保真DNA聚合酶介导的引物延伸反应。用多重PCR反应体系检测临床已知分别含CD26和TATAbox-28突变热点患者的DNA标本。结果对野生模板而言,仅有野生型等位基因相关引物有产物产生,而突变型等位基因位点特异性引物无产物产生。反之,使用突变模板,仅突变型等位基因位点相关引物有产物产生,而野生型等位基因位点特异性引物无产物产生。高保真DNA聚合酶介导的多重引物延伸反应筛查含有CD26或TATAbox-28突变的患者DNA标本时显示,突变引物混合物只有相应突变位点的产物产生,而野生引物混合物则有除突变位点以外的其他5个位点的产物产生。结论建立了基于高保真DNA聚合酶的筛查β地中海贫血基因热点突变的PCR技术。     

建立RT-ARMS-qPCR系统定量测定含A1555G突变的线粒体DNA拷贝数

目的建立RT-ARMS-qPCR（real time-amplification refractory mutation system-quantitative PCR）系统定量测定含线粒体DNA（mitochondrial DNA,mtDNA）A1555G位点突变的片段的拷贝数,为阐明线粒体耳聋临床表型多样性的分子生物学基础奠定基础。方法根据ARMS的基本原理设计引物,在引物3’端插入错配碱基AC建立RT-ARMS-qPCR系统,优化定量PCR体系,并进行方法学评价。经PCR分别扩增相应突变型和野生型的片段,将其克隆到pGEM-T Easy载体上,构建质粒标准品;同时对含突变型和/或野生型mtDNA 1555位点的片段的拷贝数进行定量检测。结果RT-ARMS-qPCR系统用于检测含mtDNA 1555位点的片段,线性检测范围为102-108拷贝数/μl,检测灵敏度为1×102拷贝数/μl,其批内变异系数（CV）为1.34%,批间CV为1.96%,重复性好;突变型和野生型引物分别只扩增相应片段,特异性好。结论RT-ARMS-qPCR系统适合于定量检测含mtDNA A1555G点突变的线粒体DNA片段,结果稳定、准确,有助于阐明线粒体耳聋严重程度的分子基础。     

RT-ARMS-qPCR定量测定线粒体耳聋患者mtDNA A1555G位点突变

目的 探讨RT-ARMS-qPCR(real time amplification refractory mutation system quantitativePCR)系统定量测定线粒体DNA(mitochondrial DNA,mtDNA)A1555G位点突变在线粒体耳聋发病机制研究中的价值.方法 以PeR扩增含mtDNA 1555位点的片段,并将其克隆到pGEM-T Easy载体上,构建质粒标准品;在引物3'端插入错配碱基AC建立RT-ARMS-qPCR系统,对含突变型和野生型mtDNA 1555位点片段的12例线粒体耳聋患者进行定量检测.结果 RT-ARMS-qPCR系统在检测1个含野生型mtDNA 1555的重组质粒DNA模板时,其批内变异系数(CV)为1.34%,批间CV为1.96%,线性范围为102-108拷贝/ul;突变型或野生型引物只特异扩增相对应的序列,特异性好;突变型/野生型mtDNA拷贝数及突变型所占的百分比与耳聋的严重程度相关(r=0.771,P=0.003),突变型mtDNA所占的比例越高,耳聋程度越严重.结论 RT-ARMS-qPCR系统适合于定量检测mtDNAA1555G点突变的线粒体DNA片段,结果特异、稳定、准确.线粒体耳聋的严重程度与含突变型和野生型mtDNA 1555位点的拷贝数比例有关.     

子宫内膜癌PTEN基因968delA突变检测技术平台的构建及初步应用

目的 构建子宫内膜癌PTEN基因968delA突变检测技术平台,为临床分析PTEN基因968delA突变与子宫内膜癌的相关性提供技术支持。方法 设计PTEN基因968delA位点的特异性硫化修饰引物,以本实验室前期构建的包含PTEN基因968delA位点的突变型质粒和野生型质粒为模板,进行高保真聚合酶介导的双向引物延伸反应,采用正交设计进行PCR条件优化,再将其优化后采用突变敏感性分子开关技术检测从南华大学附属第一医院收集的62例临床患者子宫内膜组织样本PTEN基因968delA位点突变。结果 突变敏感性分子开关技术检测PTEN基因968delA位点最佳PCR反应条件为：30个循环、模板DNA(10 ng/μL)0.3μL、引物(10μmol/L)0.5μL、退火温度61℃,灵敏度达10^-3 ng/μL。62例子宫内膜癌组织与21例正常子宫内膜组织标本均未发现PTEN基因968delA突变。结论 成功构建了子宫内膜癌PTEN基因968delA突变检测技术平台,为该技术在PTEN基因968delA的突变筛查中的应用提供了依据。     

基因突变敏感性分子开关检测β地中海贫血基因突变

目的:采用高保真DNA聚合酶介导的基因突变敏感性分子开关准确、快速检测β地中海贫血。方法:首先提取正常人血液基因组DNA,根据已知β珠蛋白基因热点突变CD41-42、IVS2-654区域序列,分别设计突变序列扩增引物,利用低保真酶进行引物延伸反应,将其PCR产物克隆到pMD19-T载体,得到β地中海贫血常见的两个突变位点的基因突变克隆:CD41-42、IVS2-654,然后以这两个突变位点为检测靶点,分别设计3′末端与野生型基因位点或突变基因位点配对的引物,硫化磷酸修饰3′末端并偶联高保真DNA聚合酶构成的基因突变敏感性分子开关,对含有相应突变的阳性质粒模板及正常人基因组DNA模板进行引物延伸反应,并通过凝胶成像系统对其进行分析。结果:当引物与模板完全配对时,引物被延伸,有PCR产物;当引物与模板不完全配对时,引物不被延伸,无PCR产物。结论:高保真DNA聚合酶介导的基因突变敏感性分子开关能准确、快速筛查β地中海贫血CD41-42、IVS2-654突变,提示其在单基因遗传病的诊断中具有广阔的应用前景。     

EGFR基因G719S和T790M突变载体的构建及临床应用研究

目的构建与宫颈癌组织表皮生长因子受体(epidermal growth factor receptor,EGFR)基因G719S和T790M位点突变型重组载体,利用其建立分子开关平台检测宫颈癌EGFR基因突变。方法以野生型重组质粒为模板,利用重叠PCR技术,得到突变型融合目的 DNA片段,再将此目的片段连接入p MD19-T质粒中,构建成突变型重组载体,将其转化入大肠埃希菌E.coli DH5α感受态细胞进行表达,用菌液PCR和基因组测序进行鉴定。设计特异性检测引物,建立分子开关检测平台用于临床宫颈癌样本的检测。结果通过基因组测序证实G719S和T790M突变位点成功引入,定点突变载体构建成功。成功建立了分子开关检测平台用于宫颈癌组织DNA的检测。结论利用重叠PCR技术简便、高效地构建了EGFR基因突变重组载体,并建立了分子开关检测平台,为基因定点突变及临床上检测EGFR基因突变提供了新的技术手段。     

多重等位基因PCR检测线粒体12S rRNA基因突变

目的 探讨多重等位基因PCR法同时检测氨基糖甙类药物性耳聋相关的线粒体12S rRNA基因A1555G和C1494T突变的临床应用价值.方法 以3种基因型(野生型、A1555G突变型和C1494T突变型)的质粒标准品为模板,分别设计针对线粒体1555和1494位点野生型和突变型的特异性引物.用多重等位基因PCR技术同时检测A1555G和C1494T突变,并初步用于138例非综合征型耳聋患者的临床基因突变检测分析,最后通过DNA测序法评估其准确性.结果 采用多重等位基因特异性PCR同时检测138例非综合征型耳聋患者中A1555G和C1494T突变的检出率为7.97%(11/138),其中,A1555G突变型10例,C1494T突变型1例;DNA测序分析检测突变型检出率为7.97%(11/138).2种方法具有极好的一致性(Kappa=1.000,P＜0.01).结论 多重等位基因PCR是一种简便、准确、有效的A1555G和C1494T突变检测方法,可用于鉴定氨基糖甙类药物性耳聋相关的线粒体12S rRNA基因突变,从而有效预防氨基糖甙类药物性耳聋的发生.

Abstract：

Objective To investigate the clinical application of multiplex allele-specific PCR assays for simultaneous detection of the mitochondrial 12S rRNA A1555G and C1494T mutations associated with aminoglycoside-induced hearing impairment.Methods Three standard plasmids of different genotypes (wild-type, A1555G mutant and C1494T mutant) were constructed for templates and allele-specific primers aiming directly at wild-type and mutant of mitochondrial DNA nt1555 and nt1494 were designed for developing a multiplex allele-specific PCR technique to detect the A1555G and C1494T mutations.Then the method was applied to clinical screening of 138 non-syndromic hearing loss subjects and confirmed by DNA sequencing.Results Multiplex allele-specific PCR was successfully applied to the detection of A1555G and C1494T mutations in a cohort of 138 Han Chinese genetically unrelated hearing-loss subjects.Finally, 11(7.97%) unrelated affected subjects harbored the A1555G and C1494T mutations in the 12S rRNA gene(10 cases for A1555G and 1 cases for C1494T), which was well consistent with results of DNA sequencing [7.97%(11/138), Kappa=1.000, P＜0.01].Conclusion This study indicates that the multiplex allele-specific PCR assay is useful, convenient and reliable in the detection of the A1555G and C1494T mutations, which could identify the subjects at risk and effectively prevent of aminoglycoside-induced hearing loss.     

等位基因特异PCR结合熔解曲线分析快速检测线粒体DNA A1555G突变

目的建立一种线粒体DNA A1555G突变的快速检测方法。方法以45例线粒体耳聋患者为研究对象,采用等位基因特异PCR结合熔解曲线分析对线粒体DNA A1555G突变位点进行检测,根据得到的熔解曲线分析线粒体DNA A1555G突变。并与PCR产物直接测序法结果进行比较。结果线粒体DNA A1555G同质性突变时只出现一个峰且峰尖所对应的Tm为(82±0.5)℃;线粒体DNA A1555G未发生突变时只出现一个峰且峰尖所对应的Tm为(79±0.5)℃;线粒体DNA A1555G异质性突变时出现2个峰且各自峰尖所对应的Tm为(82±0.5)℃和(79±0.5)℃。45例样本的检测结果与PCR产物直接测序法的结果符合率达100%。结论等位基因特异PCR结合熔解曲线分析具有操作简便、结果准确、快速等特点,可作为线粒体DNA A1555G突变检测的常规方法。     

PCR阻断联合荧光探针检测HBV基因前C区G1896A突变株

目的 研究和评估PCR扩增阻断联合荧光探针检测乙型肝炎病毒（HBV）基因前C区1896位点突变的新方法.方法 根据HBV DNA前C区1896位点的突变设计一系列引物,引物3′末端位于1896位,并与突变模板1896位碱基互补.在引物的倒数第2及第3位碱基设计为错配碱基,以增加反应的特异性.结果 以2个错配碱基的突变型引物对野生型质粒进行PCR扩增,具有显著的阻断作用,对1896位突变型质粒无阻断作用,而且对其检测的最低拷贝数可达5×10^3拷贝/ml.选用该引物对95例随机采集的HBv阳性标本进行HBV前C区G1896A位碱基突变的检测,8例为阳性,其突变率为8.4%.结论 本法在临床标本检测中是一种有效的和简便的方法.     

多重PCR诊断线粒体突变聋病的临床应用价值

目的采用多重PCR和多重限制性内切酶法同时检测线粒体DNA（mitochondrial DNA，mtDNA）1555^G、3243^G,7445^G三个突变位点，探讨多重PCR法在线粒体突变聋病中的诊断价值。方法收集311例耳聋患者外周血标本，提取DNA模板，以三对引物在同一PCR反应体系中进行多重PCR扩增；产物在同一体系中用三种相应的限制性内切酶分析，同时对扩增产物进行mtDNA基因序列测定。结果采用本法检测出mtDNA1555^G。点突变20例，7444^A点突变1例，结果与测序相符。结论多重PCR和酶切法可同时检测多个mtDNA突变位点，利用这一方法可快速简捷地诊断线粒体突变聋病，便于临床推广应用。     

Mitochondrial gene mutation

Mitochondrial DNA(mtDNA) anomaly was emerging as a cause of idiopathic cardiomyopathy in addition to sarcomeric gene mutation. Meanwhile, several point mutations and deletions in mtDNA initially recognized as major causes of mitochondrial encephalomyopathies are now clarified to share 1% cause of diabetes mellitus. These results indicate that mtDNA mutations will be a significant candidate for cardiomyopathies. Screening of cardiomyopathic patients with mtDNA point mutations revealed that there were at least several % of mtDNA anomaly (MELAS type) among them. They also showed specific findings in ultrastructures of the cardiac muscle.     

Identification of G6PD Mediterranean mutation by amplification refractory mutation system

Aim: To examine the plasma nitrate/nitrite (NOx—two end products of the nitric oxide metabolism) and endothelin (ET) concentrations, and response to acute adrenaline induced hypertension in diabetic rats. Materials and methods: Four groups of 4-month-old rats were used: control rats (C, n=10) rats received adrenaline (A, 40 μg/kg i.v., n=10), rats received streptozotocin (S, 50 mg/kg i.v., n=8), and rats received STZ and adrenaline (SA, n=9). The experiments were performed 4 weeks after the STZ administration. Plasma NOx, ET, glucose, and mean arterial blood pressure (MAP) were measured. Results: Plasma ET concentrations were significantly increased in diabetic rats (S and SA) in comparison with the controls and adrenaline-only administered rats. NOx concentrations in diabetic groups (S and SA) were significantly decreased in comparison with the controls. Acute adrenaline induced hypertension in diabetes leads to a significant decrease of NOx concentrations in comparison with the controls, adrenaline-only administered and STZ-only administered rats. There was no difference between the MAP in diabetic and control rats. Adrenaline injection caused a significant increase of MAP in A and SA groups. Plasma glucose concentrations in diabetic rats (S and SA) were significantly increased in comparison with the nondiabetic groups (C and A). There was a weak but significant correlation between the NOx and ET concentrations in the controls, which probably reveal the balance between these vasoactive factors. In A, S, and SA groups, no significant correlation between the NOx/ET was found. Conclusion: An impairment of the NOx and ET formation could be involved in the pathogenesis of diabetes mellitus and especially acute hypertension and diabetes. A lack of correlation between the NOx and ET probably indicated that in diabetes and acute hypertension, a primary mechanism of compensatory nitric oxide might be lost.     

Uromodulin mutation and hyperuricemia

The discovery of uromodulin mutations as a cause of FJHN and MCKD2 raises a new question; Why the mutant uromodulin causes uricemic underexcretion and hyperuricemia? Moreover, an old and still unsolved question is now highlighted; What is the physiological function of uromodulin? Recent experimental data on intracellular trafficking of uromodulin mutants and histopathological findings on renal biopsy specimens of patients are introduced. Hypotheses on mechanisms of FJHN/MCKD2 and supporting and contrary experimental findings are reviewed.     

血小板糖蛋白Ⅰbα因子突变（A156V）导致其与血管性血友病因子 …

目的：研究在流休切应力作用下表达突变的细胞与固着的血管性血友病因子（ｖＷＦ）相互作用中ＧＰⅠｂα突变（Ａ１５６Ｖ）的意义。方法在ＧＰⅠｂαｃＤＮＡ中直接诱发的突变克隆到哺乳类表达载体ｐＤＸ的ＥｃｏＲⅠ位点,随后将突变的ｃＤＮＡ转染在ＣＨＯβⅨ细胞。人的ｖＷＦ通过甘氨酸和氯化钠沉淀及在Ｓｅｐｈａｒｏｓｅ４Ｂ柱分离的方法从血液冷沉淀制剂中纯化。纯化的ｖＷＦ固着在盖玻片上,在平行板液流室中进行细胞滚动研     

SPG4型和SPG31型遗传性痉挛性截瘫的MRI研究

目的：探讨SPG4型和SPG31型遗传性痉挛性截瘫（HSP）的MRI特征。方法：对经基因确诊的SPG4型和SPG31型2个家系8例HSP患者的MRI图像进行分析,并与16例性别及年龄相匹配的健康对照者MRI图像进行对照研究。采用1.5T MRI扫描仪对24例受试者行颅脑及脊髓MRI检查,分别测量C2、C7、T4、T9椎体水平脊髓横断面积,测量结果进行统计学分析。结果：8例患者颅脑MRI检查均未见明显异常。SPG31型HSP患者C2、C7、T4、T9椎体水平脊髓横断面积分别是（50.13±3.43）mm2、（40.45±2.00）mm2、（22.03±4.55）mm2、（26.10±4.55）mm2,与其对照组间差异有统计学意义（P值均<0.007）。SPG4型HSP患者脊髓横断面积与其对照组间差异无统计学意义。结论：SPG4型和SPG31型HSP患者颅脑MRI表现正常;SPG4型HSP患者脊髓MRI未见异常;SPG31型HSP患者可见颈髓及胸髓萎缩,蛛网膜下腔扩大。