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，由 DNA 双链断裂 (DSB) 引发的高水平重组仅在 DNA 复制后发生。然而，DSB 形成如何与 DNA 复制耦合尚不清楚。我们检查了几种 DNA 复制蛋白在粟酒裂殖酵母中这种偶联中的作用，现在表明，核糖核苷酸还原酶 (RNR) 是脱氧核糖核苷酸合成的限速酶，也是 DNA 合成抑制剂羟基脲 (HU) 的靶标，是 DNA 复制的间接需要。 DSB 的形成与 DNA 复制有关。然而，在 DNA 复制检查点蛋白 Rad1p、Rad3p、Rad9p、Rad17p、Rad26p、Huslp 或 Cdslp 的功能受到损害的细胞中，在不存在或存在 HU 的情况下，DSB 形成的发生频率相似。 HU处理的突变细胞中的DSB发生在正常位点并且与重组相关。我们提出，减数分裂 S 期的序列和重组的启动是由 DNA 复制检查点蛋白协调的。激酶 Cdc2p 是真核生物有丝分裂和减数分裂过程中进入核分裂并进行核分裂的中央调节因子。 Cdc2p 在有丝分裂开始时通过酪氨酸 15 去磷酸化而被激活，其磷酸化状态主要由激酶 Weel p 和磷酸酶 Cdc25p 决定。在裂殖酵母中，叉头型转录因子 Mei4​​p 是减数分裂期间许多基因表达所必需的，mei4 突变细胞在减数分裂 I 之前停滞。然而，mei4 细胞中细胞周期停滞的机制仍不清楚。我们现在表明，cdc25+是Mei4p控制进入减数分裂I的重要靶标。Cdc2p在酪氨酸15上的强制去磷酸化因此在mei4突变细胞中诱导减数分裂I而没有延迟，尽管没有形成孢子。我们认为 Mei4​​p 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 的限速调节因子。

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*.