Untersuchung des Zusammenhanges zwischen der Funktion pflanzlicher microRNAs und der DNA-Methylierung des PHABULOSA Locus in Arabidopsis thaliana

拟南芥植物microRNA功能与PHABULOSA位点DNA甲基化关系的研究

• 批准号: 31968340
• 负责人: Professor Dr. Stephan Wenkel
• 金额: --
• 依托单位: Department of Plant Biology
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/31968340?language=en
• 关键词: Untersuchung; des; Zusammenhanges; zwischen; der

This proposal aims to unravel the biological function of genie methylation observed at the PHABULOSA (PHB) locus in Arabidopsis thaliana. PHB is a key transcription factor required for the establishment of organ polarity in the Arabidopsis leaf. Recently it has been shown that the levels of PHB messenger RNA (mRNA) are controlled by microRNA165/166 (McConnell et al., 2001; Rhoades et al.f 2002; Mallory et al., 2004) and that microRNA/mRNA-interaction is required for methylation of a coding region within the PHB locus downstream of the microRNA complementary site (Bao et al., 2004). Although siRNAs are known to direct methylation of homologous DMA sequences (Mette et al., 2000), methylation of DMA is a function which has so far not been ascribed to microRNAs. Furthermore the machinery involved in the microRNA dependent methylation process appears to be different from that responsible for siRNA-mediated methylation as the sequences are not homologous to the miRNA and are more distantly located downstream. This points towards a novel feature of microRNAs being able to direct chromosomal modification in cis. We do not currently understand the biological role of this coding sequence methylation at the PHB locus. However, lower downstream methylation levels were observed in DNA samples made from tissues enriched for stem cells indicating that the methylation may be a developmentally controlled process. Our aim is to unravel the biological role and identify proteins involved in the methylation process hoping to gain a deeper understanding of how microRNAs control important developmental processes.

该提案旨在揭示拟南芥 PHABULOSA (PHB) 基因座上观察到的基因甲基化的生物学功能。 PHB 是拟南芥叶中建立器官极性所需的关键转录因子。最近有研究表明，PHB 信使 RNA (mRNA) 的水平受 microRNA165/166 控制（McConnell 等人，2001；Rhoades 等人，2002；Mallory 等人，2004），并且 microRNA/mRNA 相互作用microRNA 互补位点下游 PHB 位点内编码区的甲基化是必需的（Bao 等，2004）。尽管已知 siRNA 可以指导同源 DMA 序列的甲基化（Mette 等人，2000），但 DMA 的甲基化功能迄今为止尚未归因于 microRNA。此外，参与 microRNA 依赖性甲基化过程的机制似乎与负责 siRNA 介导的甲基化的机制不同，因为序列与 miRNA 不同源并且位于下游更远。这表明 microRNA 的一个新特征是能够以顺式方式指导染色体修饰。我们目前还不了解 PHB 基因座的编码序列甲基化的生物学作用。然而，在富含干细胞的组织制成的 DNA 样本中观察到较低的下游甲基化水平，表明甲基化可能是一个发育控制的过程。我们的目标是揭示其生物学作用并鉴定参与甲基化过程的蛋白质，希望更深入地了解 microRNA 如何控制重要的发育过程。