Cell cycle checkpoint control

细胞周期检查点控制

• 批准号: 17370072
• 负责人: MURAKAMI Hiroshi
• 金额: $ 9.34万
• 依托单位: NAGOYA CITY UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17370072/
• 关键词: genetics; gene; cancer

During meiosis, high levels of recombination initiated by DNA double-strand breaks (DSBs) occur only after DNA replication. How DSB formation is coupled to DNA replication is unknown, however. We examined several DNA replication proteins for a role in this coupling in Schizosaccharomyces pombe and now show that ribonucleotide reductase (RNR), the rate-limiting enzyme of deoxyribonucleotide synthesis and the target of the DNA synthesis inhibitor hydroxyurea (HU), is indirectly required for DSB formation linked to DNA replication. In cells in which the function of the DNA replication checkpoint proteins Rad1p, Rad3p, Rad9p, Radl7p, Rad26p, Huslp, or Cdslp was compromised, however, DSB formation occurred at similar frequencies in the absence or presence of HU. The DSBs in the HU-treated mutant cells occurred at normal sites and were associated with recombination. We propose that the sequence of meiotic S phase and initiation of recombination is coordinated by DNA replication checkpoint proteins.The kinase Cdc2p is a central regulator of entry into and progression through nuclear division during mitosis and meiosis in eukaryotes. Cdc2p is activated at the onset of mitosis by dephosphorylation on tyrosine-15, the phosphorylation status of which is determined mainly by the kinase Weel p and the phosphatase Cdc25p. In fission yeast, the forkhead-type transcription factor Mei4p is required for expression of many genes during meiosis, with mei4 mutant cells arresting before meiosis I. The mechanism of cell cycle arrest in mei4 cells has remained unknown, however. We now show that cdc25+ is an important target of Mei4p in control of entry into meiosis I. Forced dephosphorylation of Cdc2p on tyrosine-15 thus induced meiosis I in mei4 mutant cells without a delay, although no spores were formed. We propose that Mei4p acts as a rate-limiting regulator of meiosis I by activating cdc25+ transcription in coordination with other meiotic events.

在减数分裂期间，DNA双链断裂（DSB）引发的高水平重组仅在DNA复制后才发生。但是，如何将DSB形成与DNA复制耦合是未知的。 We examined several DNA replication proteins for a role in this coupling in Schizosaccharomyces pombe and now show that ribonucleotide reductase (RNR), the rate-limiting enzyme of deoxyribonucleotide synthesis and the target of the DNA synthesis inhibitor hydroxyurea (HU), is indirectly required for DSB formation linked to DNA复制。在DNA复制检查点蛋白RAD1P，RAD3P，RAD9P，RADL7P，RAD26P，HUSLP或CDSLP的功能的细胞中，DSB形成发生在类似的频率下，在不存在HU的情况下。 HU处理的突变细胞中的DSB发生在正常位置，与重组有关。我们建议，减数分裂的序列和重组的启动是通过DNA复制检查点蛋白协调的。激酶CDC2P是真核生物中有丝分裂和减数症期间通过核分裂进入和进展的中心调节剂。通过在酪氨酸-15上的去磷酸化开始，在有丝分裂开始时激活CDC2P，其磷酸化状态主要由激酶WEEL P和磷酸酶CDC25P确定。在裂变酵母中，在减数分裂过程中表达许多基因需要叉头型转录因子MEI4P，而MEI4突变细胞在减数分裂I。MEI4细胞中细胞周期停滞的机制仍未知为。现在，我们表明CDC25+是控制进入减数分裂的重要靶标。Cdc2p在酪氨酸15上的强迫去磷酸化，从而诱导了MEI4突变细胞中的减数分裂I，尽管没有孢子形成孢子。我们建议MEI4P通过与其他减数分裂事件协调激活CDC25+转录来充当减数分裂I的限制调节剂。

项目成果

A checkpoint control linking meiotic S phase and recombination initiation in fission yeast.

连接裂殖酵母减数分裂 S 期和重组起始的检查点控制。

• 发表时间: 2005
• 期刊: Proc.Natl.Acad.Sci.USA 102
• 作者: Y.Tonami;H.Murakami;K.Shirahige;M.Nakanishi
• 通讯作者: M.Nakanishi

Cdc2p and Cdcl3p is required for cell cycle arrest induced by defective RNA splicing in fission yeast

Cdc2p 和 Cdcl3p 是裂殖酵母中 RNA 剪接缺陷诱导的细胞周期停滞所必需的

• 发表时间: 2005
• 期刊: J Biol Chem 280
• 作者: M.Shimada;C.Namikawa-Yamada;M.Nakanishi;H.Murakami*.
• 通讯作者: H.Murakami*.