Single sperm analysis of the trinucleotide repeats in the Huntington's disease gene: quantification of the mutation frequency spectrum.
Single sperm analysis of the trinucleotide repeats in the Huntington's disease gene: quantification of the mutation frequency spectrum.
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亨廷顿病基因中三核苷酸重复的单精子分析：突变频谱的量化。
DOI：
10.1093/hmg/4.9.1519
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发表时间：
1995
影响因子：
3.5
通讯作者：
Gusella,JF
中科院分区：
文献类型：
--
作者：
Leeflang,EP;Zhang,L;Tavaré,S;Hubert,R;Srinidhi,J;MacDonald,ME;Myers,RH;deYoung,M;Wexler,NS;Gusella,JF
从3名患者和2名正常人的923个单个精子中扩增出亨廷顿病基因的CAG三联体重复区。在475个精子(0.6%)中，平均大小等位基因(15-18个重复)仅显示3个收缩突变。重复30次的正常等位基因突变频率为11%。36个重复的中间等位基因突变频率为53%，8%的配子有扩展，使等位基因大小进入HD疾病范围(38个重复)。疾病等位基因(38-51个重复)突变频率很高(92-99%)。随着重复次数的增加，扩张的频率、每次扩张增加的平均重复次数和观察到的最大扩张的大小都显著增加。收缩频率似乎也随着等位基因大小的增加而增加，但当重复次数超过36时，收缩频率会降低。我们的精子分型数据是离散的，而不是由混合精子的PCR产物涂片组成。这使得可以将观察到的突变频谱与使用离散随机模型计算的分布进行比较，该模型基于当前分子扩张过程的想法。当模型指定在聚合酶通过重复区域的过程中添加随机数量的重复时，发现了一个很好的拟合。
The CAG triplet repeat region of the Huntington's disease gene was amplified in 923 single sperm from three affected and two normal individuals. Average-size alleles (15–18 repeats) showed only three contraction mutations among 475 sperm (0.6%). A 30 repeat normal allele showed an 11% mutation frequency. The mutation frequency of a 36 repeat intermediate allele was 53% with 8% of all gametes having expansions which brought the allele size into the HD disease range (38 repeats). Disease alleles (38–51 repeats) showed a very high mutation frequency (92–99%). As repeat number increased there was a marked elevation in the frequency of expansions, in the mean number of repeats added per expansion and the size of the largest observed expansion. Contraction frequencies also appeared to increase with allele size but decreased as repeat number exceeded 36. Our sperm typing data are of a discrete nature rather than consisting of smears of PCR product from pooled sperm. This allowed the observed mutation frequency spectra to be compared to the distribution calculated using discrete stochastic models based on current molecular ideas of the expansion process. An excellent fit was found when the model specified that a random number of repeats are added during the progression of the polymerase through the repeated region.