A novel Mcm1-dependent element in the SWI4, CLN3, CDC6, and CDC47 promoters activates M/G(1)-specific transcription
A novel Mcm1-dependent element in the SWI4, CLN3, CDC6, and CDC47 promoters activates M/G(1)-specific transcription
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DOI：
10.1101/gad.11.10.1277
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发表时间：
1997-05-15
影响因子：
10.5
通讯作者：
Breeden, LL
中科院分区：
文献类型：
--
作者：
McInerny, CJ;Partridge, JF;Breeden, LL
我们已经鉴定出一种新的启动子元件，可以在酿酒酵母中赋予 M/G(1) 特异性转录。我们将这个元件称为 ECB（早期细胞周期盒），首先在 SWI4 启动子中发现，但它也存在于 G(1) 细胞周期蛋白 CLN3 的启动子中，以及三个 DNA 复制基因 CDC6、CDC47 和 CDC46 的启动子中。所有五个基因的转录本在细胞周期中振荡，并在 M/G(1) 边界处达到峰值，报告构建体中分离的 ECB 元件也是如此。 ECB 元件含有 Mcm1 体外结合的 Mcm1 结合位点，而 Mcm1-VP16 融合体将组成型激活子放置在体内 Mcm1 结合位点上，可以解除包含 ECB 的启动子的调节。 Mcm1 是一种转录因子，也是微型染色体维持所必需的。我们提供的证据表明 mcm1 突变体的复制缺陷可以通过异位 CDC6 转录来抑制。 SWI4 和 CLN3 的周期性表达可能对细胞周期进展很重要，因为我们发现这些基因都是单倍体不足且限制 G(1) 进展的速率。我们认为，ECB 调节的基因产物通过调节 CLN1 和 CLN2 转录以及作为复制起点上起始复合物的组成部分，在促进 S 期启动中发挥着关键作用。
We have identified a novel promoter element that confers M/G(1)-specific transcription in Saccharomyces cerevisiae. This element, which we call an ECB (early cell cycle box), was first identified in the SWI4 promoter, but it is also present in the promoter of a G(1) cyclin CLN3, as well as in the promoters of three DNA replication genes: CDC6, CDC47, and CDC46. Transcripts from all five of these genes oscillate during the cell cycle and peak at the M/G(1) boundary, as do isolated ECB elements in reporter constructs. The ECB element contains an Mcm1 binding site to which Mcm1 binds in vitro, and an Mcm1-VP16 fusion, which places a constitutive activator on Mcm1-binding sites in vivo, can deregulate ECB-containing promoters. Mcm1 is a transcription factor that is also required for minichromosome maintenance. We provide evidence that the replication defect of mcm1 mutants can be suppressed by ectopic CDC6 transcription. Periodic expression of SWI4 and CLN3 may be important for cell cycle progression, as we find that these genes are both haploinsufficient and rate limiting for G(1) progression. We suggest that ECB-regulated gene products play critical roles in promoting the initiation of S-phase, both by regulating CLN1 and CLN2 transcription and as components of the initiation complex on origins of replication.