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Diversity and functional differentiation of preinitiation complex of transcription in plants

植物转录起始复合体的多样性和功能分化

基本信息

批准号：
17370017
负责人：
OBOKATA Junichi
金额：
$ 9.94万
依托单位：
Nagoya 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 2007
项目状态：
已结题

项目摘要

Core promoter is a region where preinitiation complex containing RNA polymerase II assembles, and located around the transcription start sites. However, the majority of plant promoters do not have any recognizable core promoter elements, which reflects our limited understanding of plant promoters.We hut:la fed this grant project by elucidating the core promoter architecture of the plant genome. For this sake, we took the combined approach of in silico detection of novel core promoter elements and large-scale determination of transcription start sites (TSSs). We developed a novel methodology for TSS identification, using a combination of the Cap-Trapper and Massively Parallel Signature Sequencing methods. This technique, CT-MPSS, allowed us to identify 158,237 Arabidopsis TSS tags corresponding to 38,311 TSS loci, which has provided an opportunity for quantitative analysis of plant promoters for the first time. The expression characteristics of these core promoters were analyzed in resp … More ect to core promoter elements detected. by our in silico analyses, revealing that Arabidopsis promoters contain two major types with exclusive characteristics, a TATA type and a GA type. The TATA-type promoters tend to be associated with the Y Patch and Inr, and cause high-level expression with TSS clusters of sharp peak. By contrast, the GA type produces broad-type TSS clusters. Unlike mammalian promoters, plant promoters are not associated with CpG islands. However, plant-specific GA-type promoters share some characteristics with mammalian CpG-type promotersNext, we examined the functional differentiation of core promoter elements with respect to tissue-specific and light-responsive transcriptional regulation, using Arabidopsis photosynthesis genes as a model case. We made a series of swapping constructs of regulatory and core promoter segments from various genes, and their reporter fusions were introduced into plants. Analysis of the expression characteristics of these chimeric promoter constructs revealed that upstream regulatory elements each have preference to specific type of core promoter subtypes. This finding implies that the functional differentiation of core promoter subtypes may reflect the functional differentiation of transcriptional preinitiation complexes. Less

核心启动子是包含RNA聚合酶II的预起始复合物组装的区域，位于转录起始位点周围。然而，大多数植物启动子不具有任何可识别的核心启动子元件，这反映了我们对植物启动子的了解有限。我们通过阐明植物基因组的核心启动子结构来资助这个资助项目。为此，我们采用了新型核心启动子元件的计算机检测和转录起始位点（TSS）的大规模测定相结合的方法。我们结合使用 Cap-Trapper 和大规模并行签名测序方法，开发了一种新的 TSS 识别方法。 CT-MPSS技术使我们能够识别出对应于38,311个TSS位点的158,237个拟南芥TSS标签，这首次为植物启动子的定量分析提供了机会。针对检测到的核心启动子元件，对这些核心启动子的表达特征进行了分析。通过我们的计算机分析，揭示拟南芥启动子包含两种具有独特特征的主要类型：TATA 类型和GA 类型。 TATA型启动子往往与Y Patch和Inr相关，并引起尖峰TSS簇的高水平表达。相比之下，GA 类型产生广泛类型的 TSS 簇。与哺乳动物启动子不同，植物启动子与 CpG 岛无关。然而，植物特异性 GA 型启动子与哺乳动物 CpG 型启动子具有一些共同特征接下来，我们以拟南芥光合作用基因作为模型案例，研究了核心启动子元件在组织特异性和光响应转录调控方面的功能分化。我们制作了一系列来自不同基因的调控和核心启动子片段的交换构建体，并将它们的报告基因融合体引入植物中。对这些嵌合启动子构建体的表达特征的分析表明，每个上游调控元件都偏好特定类型的核心启动子亚型。这一发现意味着核心启动子亚型的功能分化可能反映了转录前起始复合物的功能分化。较少的