Role of HMGA1a and ORC interaction in origin definition and heterochromatin organization

HMGA1a 和 ORC 相互作用在起源定义和异染色质组织中的作用

• 批准号: 49045643
• 负责人: Privatdozent Dr. Robert Hock
• 金额: --
• 依托单位: Lehrstuhl für Zell- und Entwicklungsbiologie (Zoologie I)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/49045643?language=en
• 关键词: Role; HMGA1a; ORC; interaction; origin

In recent years considerable progress has been made towards elucidating the molecular mechanisms that control eukaryotic DNA replication. However, the basic question about constitution and definition of human origins is still open. Key player for origin recognition is the origin recognition complex (ORC). This protein complex is not only essential for DNA replication, but also important for the eukaryotic chromosome cycle, i.e. the organization of chromatin. Currently it is not known how ORC discriminates between these functions. Recently, we observed that the high mobility group proteins A (HMGA) not only interact with heterochromatin protein 1 (HP1), but also co-localizes and associates with ORC. Based on these findings our proposal addresses two major questions. Firstly, we propose to study the function of HMGA1a in origin definition and ORC-targeting with genetic, biochemical and imaging approaches. In particular, we aim to identify DNA-elements recognized by HMGA1a and ORC and determine the replication competence of these fragments in their native chromosomal location as well as in episomal systems. The functional relevance will be further explored using mutated proteins and siRNA experiments. Moreover, we wish to specify the molecular details of the interactions between Orc-subunits, HMGA1 and HP1 by using biochemical and imaging approaches. We will analyze the dynamics of HP1, HMGA and ORC complexes and verify the co-operation and function of such complexes after using co-expression and “knock down” strategies. The aim is to define the relevance of such co-operations for DNA replication and/or organization of heterochromatin.

近年来，在阐明控制真核 DNA 复制的分子机制方面已经取得了相当大的进展。然而，关于人类起源的构成和定义的基本问题仍然悬而未决。起源识别的关键角色是起源识别复合体（ORC）。这种蛋白质复合物不仅对于 DNA 复制至关重要，而且对于真核染色体周期（即染色质的组织）也很重要。目前尚不清楚 ORC 如何区分这些函数。最近，我们观察到高迁移率族蛋白 A (HMGA) 不仅与异染色质蛋白 1 (HP1) 相互作用，而且还与 ORC 共定位和关联。基于这些发现，我们的提案解决了两个主要问题。首先，我们建议通过遗传、生化和成像方法研究 HMGA1a 在起源定义和 ORC 靶向中的功能。特别是，我们的目标是鉴定 HMGA1a 和 ORC 识别的 DNA 元件，并确定这些片段在其天然染色体位置以及附加体系统中的复制能力。将使用突变蛋白和 siRNA 实验进一步探讨功能相关性。此外，我们希望通过使用生化和成像方法来详细说明 Orc 亚基、HMGA1 和 HP1 之间相互作用的分子细节。我们将分析HP1、HMGA和ORC复合物的动力学，并在使用共表达和“敲低”策略后验证这些复合物的合作和功能。目的是确定此类合作与 DNA 复制和/或异染色质组织的相关性。