用反向点杂交术快速检测中国人18种β—地中海贫血基因突变

β-地中海贫血(简称β-地贫)的分子基础主要是点突变。目前全球范围已发现100种以上此类突变。中国人群中有18种。随着PCR技术的应用,以等位基因特异性寡核苷酸(ASO)探针杂交为代表的多种点突变检测技术已被广泛采用,但对于像β-地贫这样有很大异质性的遗传病,采用这些技术进行基因诊断仍较困难,因现有的方法是以逐一“过筛”的策略来     

α1(Ⅰ)型前胶原基因反义重组质粒对成纤维细胞的影响

目的：研究反义RNA对成纤维细胞胶原蛋白的调控作用,探讨基因治疗增生性瘢痕的可能性。方法：将α1（Ⅰ）型前胶原基因片段反向克隆至非整合型哺乳动物表达载体pREP9的多克隆位点中,以构α1(Ⅰ)丧胶原基因反义RNA表达载体pREP9-AScoll,并籍脂质体－lipofectamine将其导入人肺HLF细胞中,运用MTT试验,电镜,3H－氨酸掺入法检测反义RNA表达载体对HLF细胞的影响。结果：外源重组体pREP9-AScoll对胶原蛋白的合成有明显抑制作用,但对细胞增殖无任何影响。结论：α1（Ⅰ）型前胶原基因反义重组质粒能有效调控胶原蛋白的合成,从而有在基因水平防治瘢痕的前景。     

营养、衰老与自由基理论

1965年Harman D提出衰老的自由基理论(free radical theory of aging)，它的提出是基于这样的前提，即所有生物的衰老和死亡是由一个受遗传因素和环境因素影响的共同过程负责。该理论认为衰老是细胞成分积累性氧化损伤的结果，是由自由基反应引起的，自由基反应参与环境、疾病和遗传控制的衰老过程有关的衰老性改变。     

反义α_1(Ⅰ)型前胶原基因片段真核细胞表达质粒的构建与鉴定

为利用反义RNA下调成纤维细胞Ⅰ型胶原基因的表达，根据α1（Ⅰ）前胶原基因的核苷酸序列，我们自行设计了6条寡核苷酸引物，从正常人外周血全基因组DNA中分别扩增α1（Ⅰ）前胶原基因的转录起始区域及第Ⅰ，Ⅱ外显子区域3个基因片段。片段长度分别为229、166、195hP。为了后续进行定向克隆，在引物上分别引入了限制性内切酶酶切位点，并附加酶切保护碱基。由于1、刀、皿、V、力型多种胶原由不间断的重复的氨基酸序列（Gly－X－Y）n组成，其中X多为脯氨酸，而Y多为羟瞄氨酸，放各种胶原基因的结构极为相似，而且基因中GC含量很高（Gl…     

α_1(Ⅰ)型前胶原基因反义重组质粒对成纤维细胞的影响

目的　研究反义RNA对成纤维细胞胶原蛋白的调控作用 ,探讨基因治疗增生性瘢痕的可能性。方法　将α1 (Ⅰ )型前胶原基因片段反向克隆至非整合型哺乳动物表达载体pREP9的多克隆位点中 ,以构建α1 (Ⅰ )型前胶原基因反义RNA表达载体pREP9 AScoll,并籍脂质体 lipofectamine将其导入人胚肺HLF细胞中 ,运用MTT试验、电镜、3H 脯氨酸掺入法检测反义RNA表达载体对HLF细胞的影响。结果　外源重组体pREP9 AScoll对胶原蛋白的合成有明显抑制作用 ,但对细胞增殖无任何影响。结论　α1 (Ⅰ )型前胶原基因反义重组质粒能有效调控胶原蛋白的合成 ,从而有在基因水平防治瘢痕的前景。     

A rapid reverse dot blot assay for all 18 β-thalassemia mutations in Chinese population

A set of allele-specific oligonucleotide (ASO) probes used for detecting all 18 β-tha-lassemia mutations found in Chinese was immobilized on two strips of Biodyne C membrane;one containing 7 pairs of oligonucleotide probes specific for the most commonly found mutant al-leles,and the other containing the remaining 11 pairs of ASO_s specific for the less commonlyfound.The membranes were hybridized with β-globin sequences amplified by polymerase chainreaction (PCR) with biotinylated primers,and then treated with Streptavidin-POD conjugateand substrates for color development.The method has been applied successfully to the detectionof all 18 Chinese β-thalassemia mutations and prenatal diagnosis of two high-risk pregnancies ofβ-thalassemia.Patients with homozygous,heterozygous and compound heterozygous alleles ofthese mutations and normal individuals could be easily distinguished by the present method.Us-ing the immobilized-probe format (reverse dot blot),it was able to screen simultaneously multi-ple β-thalassemia mutations of a DNA sample by performing hybridization only once.This assayis simple,rapid and independent of radio-isotopes and can be appplied for all 18 β-thalassemiamutations so far found in Chinese population.It is considered that this method may be usefulfor gene frequency investigation of large numbers of β-thalassemia DNA samples and used as aroutine method in the clinic laboratory.     

PCR产物直接序列分析法检出一例中国人β-地中海贫血罕见突变类型

本文报道用聚合酶链反应(PCR)产物直接测定β珠蛋白基因序列的方法,并用此方法检出一例中国人罕见的β—地中海贫血密码子14/15(+G)突变。在确定了突变位点的序列后,用相应的限制酶切图谱分析和用放射性同位素标记的等位基因特异性寡核苷酸探针进行斑点杂交,结果均证明测序结果的正确性。     

Detection of rare mutation of β-thalassemia by direct sequence analysis of the PCR products

A technique of direct sequence analysis of β-globin gene with the products of amplifi-cation by polymerase chain reaction (PCR) was reported and a case of β-thalassemia with therare mutation in Chinese,‘codon 14/15 (+G)’ was detected by this method.After the se-quence of the mutation site was determined,an analysis of the restriction map of the gene anddot blot hybridization with radioactive allele specific oligonucleotide probe was designed to con-firm the result of DNA sequencing.