High-resolution genome-wide analysis of irradiated (UV and γ-rays) diploid yeast cells reveals a high frequency of genomic loss of heterozygosity (LOH) events.
High-resolution genome-wide analysis of irradiated (UV and γ-rays) diploid yeast cells reveals a high frequency of genomic loss of heterozygosity (LOH) events.
复制标题
DOI：
10.1534/genetics.111.137927
复制
发表时间：
2012-04
期刊：
影响因子：
3.3
通讯作者：
Petes TD
中科院分区：
文献类型：
--
作者：
St Charles J;Hazkani-Covo E;Yin Y;Andersen SL;Dietrich FS;Greenwell PW;Malc E;Mieczkowski P;Petes TD
在二倍体真核生物中，通过同源重组修复双链DNA断裂往往会导致杂合性丢失(LOH)。以前对酿酒酵母有丝分裂重组的研究大多集中在单个染色体或单个染色体的单个区域，在该区域可以选择LOH事件。在这项研究中，我们使用两种技术(单核苷酸多态微阵列和高通量DNA测序)在平均1kb的分辨率下检测了二倍体酵母菌株的全基因组杂合性缺失。在未经处理的细胞和接受γ辐射或紫外线(UV)辐射的细胞中，我们检查了V染色体上的选定LOH事件和整个基因组中的未选定事件。我们的分析表明：(1)自发和损伤诱导的有丝分裂基因转换区比减数分裂基因转换区大三倍以上，而且与交叉相关的转换区通常比与交叉相关的那些更长、更复杂；(2)大多数交叉和转换反映了在同一位置断裂的两个姐妹染色单体的修复；以及(3)UV和γ辐射在不会造成显著活力损失的辐射剂量下都有效地诱导LOH。利用高通量DNA测序，我们还检测到了γ射线和紫外线诱导的新突变。据我们所知，我们的研究是第一次在真核生物中对DNA损伤诱导的LOH事件进行高分辨率全基因组分析。
In diploid eukaryotes, repair of double-stranded DNA breaks by homologous recombination often leads to loss of heterozygosity (LOH). Most previous studies of mitotic recombination in Saccharomyces cerevisiae have focused on a single chromosome or a single region of one chromosome at which LOH events can be selected. In this study, we used two techniques (single-nucleotide polymorphism microarrays and high-throughput DNA sequencing) to examine genome-wide LOH in a diploid yeast strain at a resolution averaging 1 kb. We examined both selected LOH events on chromosome V and unselected events throughout the genome in untreated cells and in cells treated with either γ-radiation or ultraviolet (UV) radiation. Our analysis shows the following: (1) spontaneous and damage-induced mitotic gene conversion tracts are more than three times larger than meiotic conversion tracts, and conversion tracts associated with crossovers are usually longer and more complex than those unassociated with crossovers; (2) most of the crossovers and conversions reflect the repair of two sister chromatids broken at the same position; and (3) both UV and γ-radiation efficiently induce LOH at doses of radiation that cause no significant loss of viability. Using high-throughput DNA sequencing, we also detected new mutations induced by γ-rays and UV. To our knowledge, our study represents the first high-resolution genome-wide analysis of DNA damage-induced LOH events performed in any eukaryote.