Molecular mechanisms regulating Poly(ADP-ribosyl)ation pathway in living cells

发育过程受到严格控制，它们的破坏会导致病理。染色质因子通过控制特定基因座的染色质状态来协调多个发育基因的表达，从而调节发育过程。关于染色质是如何编程的，以及在发育过程中如何维持活跃或不活跃的结构域，仍有许多有待了解。多(ADP-核糖)聚合酶1(PARP1)和多(ADP-核糖)糖水解酶(PARG)(PAR酶)通过控制染色质状态和转录，在生物体发育过程中起着至关重要的作用。在这个项目中，研究人员将使用PAR途径作为模型来了解细胞如何经历快速、局部和可逆的染色质重编程来微调基因活性。这些发现将增强我们对发育基因调控的了解，并促进重新编程基因的新方法，例如通过激活存在于抑制染色质基因座的PAR酶。该项目将加强北达科他大学的研究环境，为当地不同背景的高中生和本科生提供学习发育过程的基础和生物医学方面的新机会。该项目将以果蝇为模型，重点研究PARG酶调节的分子机制。这项研究将受到这样一个假设的推动，即PARG活性的调节对于组织特异性和细胞周期特异性的聚(ADP-核糖)转化率的差异至关重要。初步数据表明，PARG没有DNA结合基序，在染色质中有两个不同的作用：1)PARP1不依赖于沉默基因的基因体，可能抑制其表达；2)结合PARP1占据的活性位点，可能与PARP1协同维持其表达。本项目将致力于研究在稳态和突变背景下，活细胞中PAR酶的靶向和调控的分子机制。这些实验将探索1)什么机制将PAR酶招募到特定的位点，以及2)什么触发和微调PAR依赖的过程，包括潜在的机制。这些成果将促进对PAR途径以及如何以新的方式进行调节的理解。该项目由生物科学局分子和细胞生物科学部门的遗传机制计划和既定的刺激竞争研究计划(EPSCoR)共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Developmental processes are tightly regulated, and their disruption leads to pathologies. Chromatin factors regulate developmental processes by controlling the chromatin state of specific loci to coordinate expression of multiple developmental genes. Much remains to be learned about how chromatin is programmed and how active or inactive domains are maintained during development. Poly(ADP-ribose) polymerase 1 (PARP1) and poly(ADP-ribose) glycohydrolase (PARG) (PAR enzymes) play a vital role during organismal development by controlling chromatin state and transcription. In this project, researchers will use the PAR pathway as a model to understand how cells undergo quick, localized and reversible chromatin reprogramming to fine tune gene activity. The findings will enhance our knowledge of developmental gene regulation and facilitate new methodology for reprogramming genes, for example through activation of PAR enzymes present in repressed chromatin loci. This project will reinforce the research environment at University of North Dakota by providing local high school and undergraduate students of different backgrounds with new opportunities to learn fundamental and biomedical aspects of developmental processes.This project will focus on the study of molecular mechanisms of PARG enzyme regulation, using Drosophila as a model. The research will be driven by the hypothesis that regulation of PARG activity is crucial for tissue-specific and cell cycle-specific differences in poly(ADP-ribosyl)ation rates. The preliminary data show that PARG, which does not have a DNA-binding motif, has two distinct roles in chromatin: 1) PARP1-independent binding to gene body of silent genes, likely to repress their expression; 2) binding of PARP1-occupied active loci, likely to maintain their expression in cooperation with PARP1. This project will focus on characterizing the molecular mechanism targeting and regulating PAR enzymes in living cells in steady-state conditions and in mutant backgrounds. The experiments will probe 1) what mechanisms recruit PAR enzymes to specific loci and 2) what triggers and fine-tunes PAR-dependent processes, including underlying mechanisms. The outcomes will advance understanding of the PAR pathway and how it might be modulated in new ways.This project is jointly funded by the Genetic Mechanisms program in the Molecular and Cellular Biosciences Division of the Directorate for Biological Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.