Mechanisms of RING1B and PRC1 complexes in transcriptional activation

RING1B和PRC1复合物在转录激活中的机制

• 批准号: 10366930
• 负责人: Lluis Morey
• 金额: $ 32.24万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10366930
• 关键词: 3-Dimensional; Acute; Address; Architecture; BT 474; Binding; Biological Assay; Biological Process; Breast Cancer Cell; Breast Cancer Model; Breast Cancer cell line; Cells; ChIP-seq; Chemicals; Chromatin; Chromatin Structure; Clustered Regularly Interspaced Short Palindromic Repeats; Complex; Coupled; DNA; Data; Development; Distal; Endocrine; Enhancers; Epigenetic Process; Estrogen Receptor alpha; Estrogens; Feedback; Fulvestrant; GREB1 gene; Gene Activation; Gene Chips; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Growth; Hi-C; Hormonal; Hormones; Human; Hybrids; Licensing; MCF7 cell; Malignant Neoplasms; Mediating; Metabolism; Metastatic breast cancer; Multiprotein Complexes; Mutation; NCOA2 gene; NCOA3 gene; Neoplasm Metastasis; Oncogenes; Oncogenic; PRC1 Protein; Polycomb; Process; Proteins; Proteomics; RNA; Regulator Genes; Regulatory Element; Reproduction; Research; Resistance; Resolution; Role; Steroid Receptors; T47D; Tamoxifen; Testing; Transcriptional Activation; Work; Xenograft Model; base; cancer cell; cohesin; experimental study; gene repression; genome-wide; genome-wide analysis; hormone therapy; human disease; in vivo; malignant breast neoplasm; mutant; novel; overexpression; paralogous gene; patient derived xenograft model; promoter; protein complex; recruit; response; stem cell fate; stem cells; steroid hormone; transcriptome sequencing; tumor; tumorigenesis

Project summary Polycomb group (PcG) complexes are multi-protein, evolutionarily conserved epigenetic machineries that regulate stem cell fate decisions and early development. Mutation and abnormal expression of Polycomb Repressive Complex 1 (PRC1) subunits are also implicated in human disease. PRC1 is a protein complex that was classically thought to mediate transcriptional repression of genes. We and others recently showed that specific PRC1 complexes, defined by the presence of one of the six mammalian PCGF paralogs, can also facilitate gene transcription in stem and cancer cells to regulate cell fate decisions and oncogenes. How PRC1 is recruited to chromatin and mediates transcriptional activation is poorly understood. We recently demonstrated that PRC1 and the estrogen receptor alpha (ER) co-occupy transcriptionally active genes and enhancers to regulate proliferation of breast cancer cells. ER is functionally activated by the steroid hormone estrogen. Once activated, ER binds to chromatin and recruits co-activators to regulate fundamental biological processes such as development, reproduction, metabolism, and cancer. Our new preliminary data show that estrogen induces rapid and dynamic recruitment to chromatin of RING1B, the core subunit of all PRC1 complexes, to activate gene transcription in a PRC1-indepenent fashion. Moreover, we found that R-loop formation and ER might be important for RING1B recruitment to chromatin, suggesting that RING1B is tethered to chromatin by different mechanisms. Importantly, RING1B is also required for ER recruitment, gene and enhancer transcriptional activation as well as chromatin organization. Our preliminary 3D chromatin architecture data also revealed that RING1B/ER-containing enhancers physically interact with estrogen-responsive genes. These results uncover potential new mechanisms for transcriptional activation mediated by RING1B upon estrogen administration. Finally, we found that RING1B is overexpressed in metastatic endocrine resistant breast cancer and that endocrine resistant cells are addicted to RING1B. We hypothesize that RING1B is a novel epigenetic regulator of estrogen-mediated gene regulation and chromatin architecture, and that RING1B depletion and chemical inhibition will decrease metastatic endocrine-resistant breast cancer. Here, we propose: to determine how RING1B is recruited to estrogen-responsive genes (Aim 1), the role of RING1B in enhancer-promoter interactions during estrogen administration (Aim 2), and the role of RING1B in endocrine resistance (Aim 3). Hi- C experiments, coupled to genome-wide studies (including gene expression profiles, chromatin accessibility assays), proteomics, and xenografts and PDX models will be used to address these central questions. Fundamentally, these findings will expand our understanding of the estrogen response and Polycomb implicated in broad biological processes including development, cellular metabolism and cancer.

项目概要 多梳群 (PcG) 复合物是多蛋白、进化上保守的表观遗传机制， 调节干细胞命运决定和早期发育。 Polycomb突变及异常表达 抑制复合体 1 (PRC1) 亚基也与人类疾病有关。 PRC1 是一种蛋白质复合物 传统上认为介导基因的转录抑制。我们和其他人最近表明 特定的 PRC1 复合物，由六种哺乳动物 PCGF 旁系同源物之一的存在所定义，也可以 促进干细胞和癌细胞中的基因转录，调节细胞命运决定和癌基因。 PRC1如何 人们对它被招募到染色质并介导转录激活知之甚少。我们最近展示了 PRC1 和雌激素受体 α (ERα) 共同占据转录活性基因和增强子 调节乳腺癌细胞的增殖。 ERα 的功能由类固醇激素雌激素激活。一次 激活后，ERα 与染色质结合并招募共激活剂来调节基本生物过程，例如 如发育、生殖、新陈代谢和癌症。我们新的初步数据表明雌激素会诱导 快速动态地招募 RING1B（所有 PRC1 复合物的核心亚基）染色质，以激活 以独立于 PRC1 的方式进行基因转录。此外，我们发现 R 环的形成和 ERα 可能是 对于 RING1B 招募到染色质很重要，表明 RING1B 通过不同的方式与染色质结合 机制。重要的是，RING1B 也是 ERα 募集、基因和增强子转录所必需的 激活以及染色质组织。我们的初步 3D 染色质结构数据还表明 含有 RING1B/ERα 的增强子与雌激素反应基因发生物理相互作用。这些结果揭示了 雌激素给药后 RING1B 介导的转录激活的潜在新机制。 最后，我们发现 RING1B 在转移性内分泌抵抗性乳腺癌中过度表达，并且 内分泌抵抗细胞对 RING1B 上瘾。我们假设 RING1B 是一种新型表观遗传调节因子 雌激素介导的基因调控和染色质结构，以及 RING1B 耗竭和化学 抑制将减少转移性内分泌耐药乳腺癌。在此，我们建议：确定如何 RING1B 被招募到雌激素反应基因（目标 1），RING1B 在增强子-启动子中的作用 雌激素给药期间的相互作用（目标 2），以及 RING1B 在内分泌抵抗中的作用（目标 3）。你好- C 实验，结合全基因组研究（包括基因表达谱、染色质可及性 分析）、蛋白质组学、异种移植和 PDX 模型将用于解决这些核心问题。 从根本上说，这些发现将扩大我们对雌激素反应和 Polycomb 的理解 广泛的生物过程，包括发育、细胞代谢和癌症。