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

发育过程受到严格的调控，它们的破坏会导致疾病。染色质因子通过控制特定位点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，还有很多有待研究。聚（adp -核糖）聚合酶1 （PARP1）和聚（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发挥重要作用。在这个项目中，研究人员将使用PAR途径作为模型来理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认识，并促进基因重编程的新方法，例如通过激活存在于被抑制染色质位点中的PAR酶。该项目将通过为当地不同背景的高中生和本科生提供学习发展过程基础和生物医学方面的新机会，加强北达科他州大学的研究环境。本项目将以果蝇为模型，重点研究PARG酶调控的分子机制。该研究将基于这样的假设：PARG活性的调节对于组织特异性和细胞周期特异性的聚（adp -核糖基）化率差异至关重要。初步数据表明，PARG不具有dna结合基序，在染色质中具有两种不同的作用：1)parp1不依赖于沉默基因的基因体结合，可能抑制其表达；2)结合PARP1占据的活性位点，可能与PARP1合作维持其表达。本项目将重点研究稳态条件和突变背景下活细胞中靶向和调控PAR酶的分子机制。实验将探索1)什么机制将PAR酶招募到特定的位点，2)什么触发和微调PAR依赖的过程，包括潜在的机制。这些结果将促进对PAR通路的理解，以及如何以新的方式调节PAR通路。该项目由生物科学理事会分子和细胞生物科学部的遗传机制计划和促进竞争性研究的既定计划（EPSCoR）共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.