Structural Insights Into Regulation of SOS Mutagenesis

SOS 诱变调控的结构见解

• 批准号: 6667937
• 负责人: MARTIN GONZALEZ
• 金额: $ 10.5万
• 依托单位: SOUTHWESTERN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6667937
• 关键词: DNA damage; DNA directed DNA polymerase; DNA repair; biological signal transduction; cell cycle; cell growth regulation; conformation; enzyme activity; protein degradation; protein sequence; protein structure function; site directed mutagenesis

DESCRIPTION (provided by applicant): The degradation of proteins is known to be an essential regulatory mechanism vital for biological processes and diseases including cell cycle progression, DNA repair, and cancer. While the majority of cellular proteins are stable, there are a small percentage of cellular proteins that are unstable, temporal acting, and function in a regulatory manner. An example of these are the Escherichia coli proteins UmuD' (UmuD) and UmuC. UmuD'C comprise an error-prone DNA polymerase, DNA polV, necessary for the survival of the bacterium following extensive DNA damage. The Umu proteins are part of a DNA damage tolerance system termed SOS mutagenesis. Recent work suggests that the mammalian counterparts of these prokaryotic error-prone polymerases may play a role in processes from cancer establishment to induction of somatic cell hypermutation of immunoglobulin genes. Therefore, DNA polV activity and regulation is an ideal model to study for two reasons: (i) the regulation of DNA polV is vital to the understanding of the SOS mutagenic response and will provide a scientific foundation for exploring the regulation of eukaryotic error-prone polymerases, and (ii) DNA polV is a highly suitable model for studying selective protein degradation, a process known to be vital for cell integrity. The mechanisms by which proteases selectively recognize these and other unstable proteins are unknown and determining these mechanisms is important in understanding how SOS mutagenesis and other biological processes are specifically regulated. It is also unknown how starvation conditions, such as those experienced by bacterial cells in stationary phase and in their natural environment, affects the protease-substrate interaction. The research proposed in this project will elaborate on the mechanism(s) of Umu instability and will address the processing of UmuD (and potentially the other Umu proteins) demonstrated during stationary phase growth. We will use numerous molecular, biochemical, and genetic techniques to achieve the following aims: 1. To test DNA polV function and regulation during stress conditions not known to induce significant DNA damage. 2. To evaluate the complexity of the degradation signals of the Umu proteins and their effect on regulation.

描述（由申请人提供）：已知蛋白质的降解是对生物过程和疾病（包括细胞周期进程、DNA 修复和癌症）至关重要的重要调节机制。虽然大多数细胞蛋白是稳定的，但也有一小部分细胞蛋白不稳定、具有暂时作用并以调节方式发挥作用。其中一个例子是大肠杆菌蛋白 UmuD' (UmuD) 和 UmuC。 UmuD'C 包含一种容易出错的 DNA 聚合酶 DNA polV，它是细菌在广泛的 DNA 损伤后生存所必需的。 Umu 蛋白是称为 SOS 诱变的 DNA 损伤耐受系统的一部分。最近的研究表明，这些原核易错聚合酶的哺乳动物对应物可能在从癌症形成到诱导体细胞免疫球蛋白基因超突变的过程中发挥作用。因此，DNA polV 活性和调控是一个理想的研究模型，原因有二：（i）DNA polV 的调控对于理解 SOS 诱变反应至关重要，并将为探索真核生物易出错的调控提供科学基础。聚合酶，以及 (ii) DN​​A polV 是非常适合研究选择性蛋白质降解的模型，已知这一过程对于细胞完整性至关重要。蛋白酶选择性识别这些和其他不稳定蛋白质的机制尚不清楚，确定这些机制对于理解 SOS 诱变和其他生物过程如何被具体调控非常重要。还不清楚饥饿条件（例如处于静止期和自然环境中的细菌细胞经历的饥饿条件）如何影响蛋白酶与底物的相互作用。该项目提出的研究将详细阐述 Umu 不稳定的机制，并将解决稳定期生长期间展示的 UmuD（以及可能的其他 Umu 蛋白）的加工问题。我们将使用多种分子、生物化学和遗传技术来实现以下目标： 1. 测试 DNA polV 在未知的应激条件下的功能和调节，以诱导显着的 DNA 损伤。 2. 评估Umu蛋白降解信号的复杂性及其调控作用。