Regulation of chromatin remodeling at meiotic recombination initiation sites

减数分裂重组起始位点染色质重塑的调控

基本信息

批准号：
11680712
负责人：
OHTA Kunihiro
金额：
$ 1.73万
依托单位：
The Institute of Physical and Chemical Research
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11680712/
关键词：
recombination hot spot meiosis fission yeast chromatin histone acetylation SAPK Mrell 染色体クロマチンヒストン転写 cAMP MAPキナーゼ

项目摘要

In eukaryotes, meiotic recombination initiation is initiated by transient meiosis-specific DNA double.strand breaks (DSBs) that occur at chromosomal sites called recombination hotspots. Recombination hotspots are often found in accessible chromosomal regions. Thus, chromatin structure plays pivotal roles in the regulation of meiotic recombination. In the present study, we investigated the molecular mechanisms on chromatin remodeling observed at the ade6-M26 recombination hotspot in fission yeast meiosis. We revealed that the stress-activated kinase cascade and the cAMP-dependent kinase (SAPK) pathways control the chromatin-remodeling at M26 counteractingly. The SAPK pathway activates the chromatin remodeling but PKA pathway operates oppositely. The M26 chromatin remodeling is also controlled by some genes responsible for meiotic induction. We found that the consensus sequence for the cAMP-responsive element (CRE) is required for the M26 hotspot activity and the chromatin remodeling. We discovered that natural CRE sites on fission yeast chromosome induce chromatin remodeling during early meiosis. Chromatin immunoprecipitation assay using anti-acetylated histone H3 and H4 revealed that M26 region is hyperacetylated in early meiosis. In addition, we found that histone acetylation by fission yeast Gcn5 histone acetyl transferase plays important roles in the regulation of chromatin remodeling, DSB formation, and recombination activation. Additional chromatin changes are induced by Rad32(the fission yeast Mrell homologue) and Rad50 recombination proteins. These results provide important clues to understand molecular basis of meiotic recombination activation.

在真核生物中，减数分裂重组起始是由短暂的减数分裂特异性 DNA 双链断裂 (DSB) 启动的，这种断裂发生在称为重组热点的染色体位点。重组热点通常出现在可接近的染色体区域。因此，染色质结构在减数分裂重组的调节中起着关键作用。在本研究中，我们研究了裂殖酵母减数分裂中 ade6-M26 重组热点处观察到的染色质重塑的分子机制。我们发现，应激激活激酶级联和 cAMP 依赖性激酶 (SAPK) 途径反向控制 M26 处的染色质重塑。 SAPK 途径激活染色质重塑，而 PKA 途径则相反。 M26 染色质重塑也受一些负责减数分裂诱导的基因控制。我们发现 cAMP 响应元件 (CRE) 的共有序列是 M26 热点活性和染色质重塑所必需的。我们发现裂殖酵母染色体上的天然 CRE 位点在减数分裂早期诱导染色质重塑。使用抗乙酰化组蛋白 H3 和 H4 进行的染色质免疫沉淀测定表明，M26 区域在减数分裂早期高度乙酰化。此外，我们发现裂殖酵母Gcn5组蛋白乙酰转移酶的组蛋白乙酰化在染色质重塑、DSB形成和重组激活的调节中发挥重要作用。其他染色质变化由 Rad32（裂殖酵母 Mrell 同源物）和 Rad50 重组蛋白诱导。这些结果为理解减数分裂重组激活的分子基础提供了重要线索。