The yeast and human FACT chromatin-reorganizing complexes solve R-loop-mediated transcription-replication conflicts.
The yeast and human FACT chromatin-reorganizing complexes solve R-loop-mediated transcription-replication conflicts.
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DOI：
10.1101/gad.234070.113
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发表时间：
2014-04-01
影响因子：
10.5
通讯作者：
Aguilera A
中科院分区：
文献类型：
--
作者：
Herrera-Moyano E;Mergui X;García-Rubio ML;Barroso S;Aguilera A
染色质重组复合物FACT在转录延伸和DNA复制中起作用，但其在复制中的作用还不清楚。在这里，Herrera-Moyano等人发现酵母突变体和FACT缺失的人类细胞中重组率增加和遗传不稳定性。结果表明FACT在R环介导的转录-复制冲突的解决中具有保守的功能。因此，这项研究将FACT在转录延伸和DNA复制中的作用联系起来。FACT（促进染色质转录）是一种染色质重组复合物，在转录延伸过程中围绕RNA聚合酶交换核小体，并在复制中发挥作用，但尚未完全了解。在这里，我们表明，重组因子是酵母FACT突变体的生存所需的，与我们检测到的Rad 52焦点和转录依赖性超重组的DNA断裂的积累一致。如γ H2 AX灶和单细胞电泳所示，断裂也在FACT-depleted人细胞中积累。此外，FACT-deficient酵母和人类细胞表现出复制障碍，在酵母中，我们通过Rrm 3的ChIP芯片（染色质免疫沉淀[ChIP]与微阵列分析相结合）证明其发生在全基因组范围内，但优先发生在高度转录的区域。引人注目的是，在酵母FACT突变体中，高水平的Rad 52灶被RNH 1过表达抑制; R环以高水平积累，并且当在FACT耗尽的人类细胞中抑制全局RNA合成时，复制变得正常。结果表明FACT在解决R环介导的转录-复制冲突中的关键功能，可能与特定的染色质组织相关。
The chromatin-reorganizing complex FACT functions in transcription elongation and DNA replication, yet its role in replication is not well understood. Here, Herrera-Moyano et al. find increased recombination rates and genetic instability in yeast mutants and FACT-depleted human cells. The results demonstrate a conserved function for FACT in the resolution of transcription–replication conflicts mediated by R loops. This study therefore links the roles of FACT in transcription elongation and DNA replication. FACT (facilitates chromatin transcription) is a chromatin-reorganizing complex that swaps nucleosomes around the RNA polymerase during transcription elongation and has a role in replication that is not fully understood yet. Here we show that recombination factors are required for the survival of yeast FACT mutants, consistent with an accumulation of DNA breaks that we detected by Rad52 foci and transcription-dependent hyperrecombination. Breaks also accumulate in FACT-depleted human cells, as shown by γH2AX foci and single-cell electrophoresis. Furthermore, FACT-deficient yeast and human cells show replication impairment, which in yeast we demonstrate by ChIP–chip (chromatin immunoprecipitation [ChIP] coupled with microarray analysis) of Rrm3 to occur genome-wide but preferentially at highly transcribed regions. Strikingly, in yeast FACT mutants, high levels of Rad52 foci are suppressed by RNH1 overexpression; R loops accumulate at high levels, and replication becomes normal when global RNA synthesis is inhibited in FACT-depleted human cells. The results demonstrate a key function of FACT in the resolution of R-loop-mediated transcription–replication conflicts, likely associated with a specific chromatin organization.
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影响因子：
16
作者：
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通讯作者：
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DOI：
10.1016/j.bbagrm.2011.07.009
发表时间：
2012-03
影响因子：
4.7
作者：
Formosa, Tim
通讯作者：
Formosa, Tim