Affected chromosome homeostasis and genomic instability of clonal yeast cultures.
Affected chromosome homeostasis and genomic instability of clonal yeast cultures.
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DOI：
10.1007/s00294-015-0537-3
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发表时间：
2016-05
期刊：
影响因子：
2.5
通讯作者：
Wnuk M
中科院分区：
文献类型：
--
作者：
Adamczyk J;Deregowska A;Panek A;Golec E;Lewinska A;Wnuk M
认为源自单个菌落的酵母细胞在基因型和表型上相同。然而，考虑到细胞的异质性，在克隆群体中监测细胞间的变异似乎也很重要。本研究采用单染色体彗星试验对酵母染色体核型进行了全面的筛选。DNA的染色体依赖性和突变依赖性变化（DNA断裂或异常复制中间体）进行了研究，使用两个单基因缺失单倍体突变体，（bub 1、bub 2、mad 1、tel 1、rad 1和tor 1）和缺乏一个感兴趣的活性基因的二倍体细胞，即BUB 1/bub 1、BUB 2/bub 2、MAD 1/mad 1、TEL 1/tel 1，RAD 1/rad 1和TOR 1/tor 1参与调控细胞周期进程、DNA修复和寿命调节。染色体脆性增加和复制应激介导的染色体异常与基因组不稳定性的发生率升高相关，即非整倍体事件-二体性、单体性和较小程度的三体性，如通过原位比较基因组杂交（CGH）判断的。tor 1长寿突变体与相对平衡的染色体稳态被认为是最基因组稳定的突变体。在克隆酵母培养过程中，自发形成的异常染色体结构可能会刺激倍性状态的变化，进而促进基因组异质性。这些改变可能在选定的突变遗传背景中更加突出，即在缺乏适当细胞周期调节和DNA修复的酵母细胞中。
Yeast cells originating from one single colony are considered genotypically and phenotypically identical. However, taking into account the cellular heterogeneity, it seems also important to monitor cell-to-cell variations within a clone population. In the present study, a comprehensive yeast karyotype screening was conducted using single chromosome comet assay. Chromosome-dependent and mutation-dependent changes in DNA (DNA with breaks or with abnormal replication intermediates) were studied using both single-gene deletion haploid mutants (bub1, bub2, mad1, tel1, rad1 and tor1) and diploid cells lacking one active gene of interest, namely BUB1/bub1, BUB2/bub2, MAD1/mad1, TEL1/tel1, RAD1/rad1 and TOR1/tor1 involved in the control of cell cycle progression, DNA repair and the regulation of longevity. Increased chromosome fragility and replication stress-mediated chromosome abnormalities were correlated with elevated incidence of genomic instability, namely aneuploid events—disomies, monosomies and to a lesser extent trisomies as judged by in situ comparative genomic hybridization (CGH). The tor1 longevity mutant with relatively balanced chromosome homeostasis was found the most genomically stable among analyzed mutants. During clonal yeast culture, spontaneously formed abnormal chromosome structures may stimulate changes in the ploidy state and, in turn, promote genomic heterogeneity. These alterations may be more accented in selected mutated genetic backgrounds, namely in yeast cells deficient in proper cell cycle regulation and DNA repair.