Multiple modes of chromatin configuration at natural meiotic recombination hot spots in fission yeast
Multiple modes of chromatin configuration at natural meiotic recombination hot spots in fission yeast
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DOI：
10.1128/ec.00246-07
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发表时间：
2007-11-01
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影响因子：
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通讯作者：
Ohta, Kunihiro
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文献类型：
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作者：
Hirota, Kouji;Steiner, Walter W.;Ohta, Kunihiro
裂殖酵母的ade 6-M26减数分裂重组热点由环状AMP反应元件（CRE）样七核苷酸序列5 '-ATGACGT-3'定义，其作为热点激活所需的Atf 1/Pcr 1异二聚体转录因子的结合位点。我们以前证明，M26序列基序周围的局部染色质改变，表现出更高的敏感性微球菌核酸酶减数分裂重组开始之前。在这项研究中，我们已经研究了这种改变是否发生在自然减数分裂DNA双链断裂（DSB）位点裂殖酵母的染色质。在最突出的DSB位点之一，mbs 1（减数分裂断裂位点1），染色质结构在DSB位点处或附近具有组成型可接近的构型。开放染色质状态的建立和DSB的形成是独立的CRE结合转录因子，Atf 1。在CRE依赖的DSB网站的染色质构型分析显示，从MBS 1的差异和相似之处。例如，tdh 1（+）基因座在DSB位点附近含有CRE共有序列，显示出减数分裂诱导的开放染色质构型，类似于ade 6-M26。相比之下，cds 1（+）基因座与mbs 1相似，表现出组成性开放构型。重要的是，Atf 1是tdh 1（+）和cds 1（+）中开放染色质形成所必需的。这些结果表明，CRE依赖的减数分裂染色质的变化是内在的过程有关的DSB形成裂殖酵母减数分裂。此外，结果表明，在自然减数分裂重组热点的染色质构型可以分为至少三个不同的类别：（i）Atf 1-CRE独立的组成型开放的染色质构型，（ii）Atf 1-CRE依赖减数分裂诱导的开放的染色质构型，和（iii）Atf 1-CRE依赖的组成型开放的染色质构型。
The ade6-M26 meiotic recombination hot spot of fission yeast is defined by a cyclic AMP-responsive element (CRE)-like heptanucleotide sequence, 5'-ATGACGT-3', which acts as a binding site for the Atf1/Pcr1 heterodimeric transcription factor required for hot spot activation. We previously demonstrated that the local chromatin around the M26 sequence motif alters to exhibit higher sensitivity to micrococcal nuclease before the initiation of meiotic recombination. In this study, we have examined whether or not such alterations in chromatin occur at natural meiotic DNA double-strand break (DSB) sites in Schizosaccharomyces pombe. At one of the most prominent DSB sites, mbs1 (meiotic break site 1), the chromatin structure has a constitutively accessible configuration at or near the DSB sites. The establishment of the open chromatin state and DSB formation are independent of the CRE-binding transcription factor, Atf1. Analysis of the chromatin configuration at CRE-dependent DSB sites revealed both differences from and similarities to mbs1. For example, the tdh1(+) locus, which harbors a CRE consensus sequence near the DSB site, shows a meiotically induced open chromatin configuration, similar to ade6-M26. In contrast, the cds1(+) locus is similar to mbs1 in that it exhibits a constitutive open configuration. Importantly, Atf1 is required for the open chromatin formation in both tdh1(+) and cds1(+). These results suggest that CRE-dependent meiotic chromatin changes are intrinsic processes related to DSB formation in fission yeast meiosis. In addition, the results suggest that the chromatin configuration in natural meiotic recombination hot spots can be classified into at least three distinct categories: (i) an Atf1-CRE-independent constitutively open chromatin configuration, (ii) an Atf1-CRE-dependent meiotically induced open chromatin configuration, and (iii) an Atf1-CRE-dependent constitutively open chromatin configuration.