Transcription-associated mutagenesis in yeast is directly proportional to the level of gene expression and influenced by the direction of DNA replication
Transcription-associated mutagenesis in yeast is directly proportional to the level of gene expression and influenced by the direction of DNA replication
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DOI：
10.1016/j.dnarep.2007.02.023
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发表时间：
2007-09-01
期刊：
影响因子：
3.8
通讯作者：
Jinks-Robertson, Sue
中科院分区：
文献类型：
--
作者：
Kim, Nayun;Abdulovic, Amy L.;Jinks-Robertson, Sue
高水平的转录与真核生物中自发突变和重组率的升高有关。为了确定转录水平是否与基因组不稳定性的程度直接相关，我们已经开发了一个四环素调控的LYS2报告系统，在酿酒酵母中在很宽的范围内调节转录水平。我们发现自发突变率与转录水平成正比，这表明RNA聚合酶通过靶点的运动启动了一个诱变过程。使用这个系统，我们还研究了两个假设，已提出来解释转录相关的诱变（TAM）：（1）转录损害复制叉的进展方向的方式和（2）DNA损伤积累在高转录条件下。通过比较酵母菌株中的突变率和光谱，将报告基因放置在靠近充分表征的复制起点的两个不同方向上，来探讨复制叉进展的影响。内源性DNA损伤积累的影响进行了研究，通过研究TAM在核苷酸切除修复缺陷或病变旁路的跨病变聚合酶Pol zeta。我们的研究结果表明，复制方向和内源性病变积累在TAM中发挥重要作用，特别是在突变谱方面。(C)2007 Elsevier B.V.保留所有权利。
A high level of transcription has been associated with elevated spontaneous mutation and recombination rates in eukaryotic organisms. To determine whether the transcription level is directly correlated with the degree of genomic instability, we have developed a tetracycline-regulated LYS2 reporter system to modulate the transcription level over a broad range in Saccharomyces cerevisiae. We find that spontaneous mutation rate is directly proportional to the transcription level, suggesting that movement of RNA polymerase through the target initiates a mutagenic process(es). Using this system, we also investigated two hypotheses that have been proposed to explain transcription-associated mutagenesis (TAM): (1) transcription impairs replication fork progression in a directional manner and (2) DNA lesions accumulate under high-transcription conditions. The effect of replication fork progression was probed by comparing the mutational rates and spectra in yeast strains with the reporter gene placed in two different orientations near a well-characterized replication origin. The effect of endogenous DNA damage accumulation was investigated by studying TAM in strains defective in nucleotide excision repair or in lesion bypass by the translesion polymerase Pol zeta. Our results suggest that both replication orientation and endogenous lesion accumulation play significant roles in TAM, particularly in terms of mutation spectra. (C) 2007 Elsevier B.V. All rights reserved.