Objective To further define the extent of chromosome 9p21 deletion in periampullary *** The loss of heterozygosity at 5 microsatellite polymorphic markers on chromosome 9p21 was detected by polymerase chain reaction...
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Objective To further define the extent of chromosome 9p21 deletion in periampullary *** The loss of heterozygosity at 5 microsatellite polymorphic markers on chromosome 9p21 was detected by polymerase chain reaction (PCR), polyacrylamide gel electrophoresis (PAGE) and silver staining in 35 specimens of periampullary neoplasms and their matching blood *** Fifty percent (4/8) of pancreatic cancer cases showed the loss of heterozygosity at one or more microsatellite loci, with the more frequent sites of D9S974 (37.5%) and D9S942 (28.6%), and some showing consecutive allelic loss. Sixty-two point five percent (5/8) of ampullary carcinoma cases showed loss of heterozygosity at one or more of the loci, frequent site of loss being D9S942 (42.9%) and the next most frequent being IFNA (37.5%) and D9S171 (37.5%). Loss of one locus was observed in 14.2% (1/7) of insulinoma. Conclusion The minimal common region of chromosome deletion in periampullary neoplasms is defined between the D9S974 and D9S942 loci within a 15?kb interval in 9p21, suggesting the involvement of a novel tumor suppressor gene in their carcinogenesis.
目的研究I型先天性厚甲症患者KRT6A基因突变情况,为建立该病的基因诊断与遗传咨询提供依据。方法提取1例I型先天性厚甲症患者及家系成员和50名正常对照外周血白细胞基因组DNA.设计针对KRT6A基因的特异引物,采用聚合酶链反应(PCR)扩增基因的全部编码序列,DNA直接测序明确具体的突变位置和方式,限制性内切酶反应验证基因突变。结果 PCR结合DNA测序发现患者KRT6A基因第7外显子存在异常;第1385位核苷酸由胸腺嘧啶(T)突变为鸟嘌呤(G),导致KRT6A角蛋白2B螺旋区末端第462位密码子由异亮氨酸(I)变成丝氨酸(S),即发生1462S错义突变。患者父母及与家系无血缘关系的50名正常对照均未发现此突变,提示I462S为一种新生突变(de novo mutation)。结论 KRT6A基因1462S新生错义突变是导致该例患者I型先天性厚甲症的特异突变。
探讨载脂蛋白B(apolipoprotein B,apoB)基因单体型与维吾尔族自然长寿之间的关系.选择新疆和田地区191名年龄90岁以上的健康维吾尔族个体为研究对象,另选53名年龄65—70岁、民族、性别、地域相匹配的正常个体为对照.采用PCR—SSP(sequence specific primer),PCR—RFLP(restriction fragment length polymorphism)和PCR-直接测序(PCR—sequencing)等技术对apoB基因第1外显子5'端信号肽插入/缺失(insertion/deletion,PD)、第26外显子Xba Ⅰ限制性片段长度多态性(restriction fragment length polymorphisms,Xba Ⅰ—RFLP)和第29外显子3'端可变数目重复序列(vaffable number of tandemly repeat,VNTR)进行分型.经Logistic回归分析显示,长寿组apoB基因X^+X^+基因型频率显著高于对照组;M,L的等位基因频率和其组成的基因型频率显著增高;在单体型分析中,长寿组中由X^+和M等位基因组成的单体型频率显著增高,而由X^-和S等位基因组成的单体型频率显著降低(均P〈0.05).研究认为:等位基因M,L,基因型X^+X^+,MM,ML,LL和单体型I—X^+-M,X^+-M与自然长寿显著正相关,可能为长寿的保护因素,而等位基因S,基因型SS和单体型X^+-S,D—S和D—X^+-S则可能是影响长寿的不利因素.
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