Degradation of origin recognition complex large subunit by the anaphase-promoting complex in Drosophila
Degradation of origin recognition complex large subunit by the anaphase-promoting complex in Drosophila
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DOI：
10.1093/emboj/cdg573
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发表时间：
2003-11-17
期刊：
影响因子：
11.4
通讯作者：
Asano, M
中科院分区：
文献类型：
--
作者：
Araki, M;Wharton, RP;Asano, M
DNA合成的起始被认为发生在由异聚体起源识别复合物（ORC）结合的位点处。以前，我们已经表明，在果蝇中，大亚基，ORC 1的水平，在细胞周期的进程中进行调制，ORC 1浓度的变化改变起源在发展过程中的利用。在这里，我们调查的机制，细胞周期依赖性降解的ORC 1。我们发现，信号在非保守的N-末端结构域的ORC 1介导其降解退出有丝分裂和在G（1）期的后期促进复合物（APC）在体内。降解似乎是APC直接作用的结果，因为N-末端结构域在体外被纯化的APC泛素化。这种受调节的蛋白水解是有效的，即使当ORC 1的转录由强组成型启动子驱动时，也足以产生蛋白质的正常时间分布。这些观察结果表明，在果蝇中，ORC 1调节的起源利用一样，在芽殖酵母Cdc 6。
The initiation of DNA synthesis is thought to occur at sites bound by a heteromeric origin recognition complex (ORC). Previously, we have shown that in Drosophila, the level of the large subunit, ORC1, is modulated during cell cycle progression and that changes in ORC1 concentration alter origin utilization during development. Here, we investigate the mechanisms underlying cell cycle-dependent degradation of ORC1. We show that signals in the non-conserved N-terminal domain of ORC1 mediate its degradation upon exit from mitosis and in G(1) phase by the anaphase-promoting complex (APC) in vivo. Degradation appears to be the result of direct action of the APC, as the N-terminal domain is ubiquitylated by purified APC in vitro. This regulated proteolysis is potent, sufficient to generate a normal temporal distribution of protein even when transcription of ORC1 is driven by strong constitutive promoters. These observations suggest that in Drosophila, ORC1 regulates origin utilization much as does Cdc6 in budding yeast.