糖尿病患者与百岁老人的线粒体细胞色素b基因单核苷酸多态性分析

Analysis of the mitochondrial cytochrome b genes single nucleotide polymorphisms (SNPs) in diabetics and centenarians

目的分析2型糖尿病(DM)患者和百岁老人线粒体细胞色素b(Cyt-b)基因的单核苷酸多态性(SNPs)。方法提取96名DM患者和96名百岁老人的外周血单个核细胞中的总DNA,用PCR法扩增、荧光DNA测序,同修订版Cambridge的碱基序列比较检出SNPs。结果两组除共同发现的29处SNPs外,每人相当的SNPs持有数以及两组除共同发现的12处氨基酸置换外,每人相当的SNPs持有数差异均有统计学意义(P=0.01,P=0.02)。从标准氨基酸配列到置换后的氨基酸配列的逸脱值(Grentham值)两组相比差异也有统计学意义(P=0.03)。结论糖尿病组线粒体Cyt-b基因持有多数的SNPs是有害的,从标准氨基酸配列到置换后的氨基酸配列的逸脱值与百岁组相比也呈现高值。

Objective We analyzed SNPss and the deviation from the standard sequence in Cyt-b of mitochondrial DNA in 96 patients with type 2 diabetes and 96 centenarians. Methods Total DNA was extracted from the blood of 96 type 2 diabetes patients and 96 centenarians. Mitochondrial Cyt-b genes were amplified by use o,f oligonucleotide primers. Sequences were analyzed by direct sequencing. Mitochondrial SNPss were identified by comparison with the revised Cambridge reference sequence. Results The number of the carried SNPss with each individual in diabetes group was significantly higher than that in centenarians group when the shared common SNPss were excluded from summation （P=0.01）. The number of carried SNPss of each individual in type 2 diabetes group was significantly higher than that in centenarians group when the shared common amino acid replacements were excluded from summation （P=0.02）. The deviation from the standard sequence in diabetes group was significantly higher than that in centenarians group （P=0. 03）. Conclusions The most mitochondrial SNPss within a species are mildly deleterious in type 2 diabetes. The deviation from the standard sequence in Cyt-b is higher in type 2 diabetes than in centenarians.