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A novel link between gene regulation and histone modifications governing islet beta-cell development and function

基因调控与控制胰岛β细胞发育和功能的组蛋白修饰之间的新联系

基本信息

批准号：
10365325
负责人：
Chad S Hunter
金额：
$ 45.83万
依托单位：
UNIVERSITY OF ALABAMA AT BIRMINGHAM
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-12-01 至 2025-11-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10365325
关键词：
Adult Affect American Architecture Autoimmune B-Cell Development B-Lymphocytes Biological Assay Cell Line Cell Lineage Cell Maturation Cell Survival Cell physiology Cells Chromatin Code Complex Data Data Set Deposition Development Diabetes Mellitus Disease Economic Burden Economics Embryo Enhancers Epidemic Epigenetic Process Essential Genes Functional disorder Gene Expression Gene Expression Regulation Gene Targeting Genes Genetic Transcription Glucose Goals Healthcare Histone H2B Histone H3 Histones Homo Hormones Human Hyperglycemia Immunoprecipitation In Vitro Individual Insulin Insulin-Dependent Diabetes Mellitus Islet Cell Islets of Langerhans Knockout Mice Knowledge LIM Domain Link Lysine Mass Spectrum Analysis Mediating Messenger RNA Modeling Modification Monoubiquitination Mus Mutation Non-Insulin-Dependent Diabetes Mellitus Nuclear Pathway interactions Patients Pharmaceutical Preparations Physiological Production Property Protein Binding Domain Proteins Publishing Quality of life Regulation Regulator Genes Reporting Repression Ring Finger Domain Role SS DNA BP Structure of beta Cell of islet Therapeutic Transactivation Transcriptional Activation Ubiquitin Work blood glucose regulation care burden chromatin remodeling combat crosslink design diabetic dimer endocrine pancreas development expectation experimental study functional loss glucose tolerance histone modification homeodomain improved in vitro Assay insight insulin regulation insulin secretion islet knock-down lentiviral-mediated mouse model novel postnatal preservation promoter recruit small hairpin RNA therapy development transcription factor transcriptome ubiquitin ligase ubiquitin-protein ligase

项目摘要

ABSTRACT Insulin-secreting b-cells within the pancreatic islets of Langerhans are absolutely required for glucose homeostasis. Loss of b-cell survival or function are hallmarks of type 1 or type 2 diabetes mellitus, respectively, which affects millions of Americans, with numbers expected to greatly increase. This has created enormous economic and health care burdens. Improvements in diabetic therapies will require the deeper understanding of novel mouse and human b-cell regulators and/or pathways directly implicated in b-cell function, including glucose-stimulated insulin secretion (GSIS). The LIM-Homeodomain class transcription factor Islet-1 (Isl1) is an islet-enriched regulator of pancreatic islet cell development, maturation, and function. Despite this, little is known of the transcriptional mechanisms or protein interactors employed by Isl1 to elicit these functions in mouse or human b-cells. To identify components of Isl1 transcriptional complexes, we performed reverse-crosslinked immunoprecipitation and mass spectroscopy experiments using mouse b-cells. We found the novel Isl1 interactors Ring Finger (Rnf)20 and Rnf40, which are E3 ubiquitin ligases that act as a homo- or hetero-dimeric complex to promote transcription via specifically mono-ubiquitinating histone H2B (H2Bub1), a precursor to active histone 3 lysine 4 trimethylation (H34me3). In vitro assays with b-cell lines revealed that (at least) Rnf20 is required for the expression of many Isl1 target genes (e.g., Glut2, MafA, Ins1), as well as GSIS. Strikingly, we also found that reduction of Rnf20 or Isl1 in b-cell lines reduced H2Bub1 and H3K4me3 marks in vitro, thus linking Isl1:Rnf20 to b-cell epigenetics. Our preliminary mouse knockout data support that Rnf20 may act as a homodimer (i.e., without Rnf40) to drive Isl1-mediated target gene regulation in mouse b-cells. Therefore, in this proposal we will compare the functional and transcriptional impacts in mouse models of Isl1 or Rnf20 deficiency, as well as in human b-cells lacking ISL1, RNF20, or RNF40. Our central hypothesis is that b-cell formation and function requires deposition of the H2Bub1 modification by recruited Isl1:Rnf20. We designed three specific aims that will examine the relative functional and gene expression importance of Isl1 and Rnf20 (and thus H2Bub1) in embryonic and adult mouse b-cells, and also in adult human b-cells. Results reported from these studies will establish Rnf20 and the H2Bub1 epigenetic mark as fundamental gene regulatory effectors of Isl1, thus impacting mouse and human b-cell function. Concepts learned will yield new insight into development of novel diabetes drugs or enhance strategies to produce therapeutic b-like cells in vitro.

摘要