Understanding the role of cell-cycle specific RNAs in hematopoiesis

(请保存在Word中，不要保存为PDF) 造血基因的错误调控可能导致功能特化血细胞的生产中断。DNA甲基化异常是造血过程中一个关键的表观遗传学特征，被认为是包括骨髓增生异常综合征(MDS)在内的大多数血液系统恶性肿瘤的标志。不幸的是，目前批准的去甲基化药物不分青红皂白地作用于整个基因组，并且具有高毒性和低特异性的代价。因此，实现选择性去甲基化的战略是必要的。我们研究的长期目标是了解如何开发一种高度特异和低毒的方法来纠正疾病状态下异常的DNA甲基化。中心假设是，在造血过程中DNA甲基化的建立是由特定的RNA控制的，能够与DNA甲基转移酶1(DNMT1)-DNMT1相互作用的RNA(DIRS)结合。DIR广泛存在，并以特定于基因座的方式防止DNA甲基化和沉默。具体地说，我们已经证明，在S阶段，造血分化的主要调节因子CCAAT/增强子结合蛋白α(CEBPA)的表达受CEBPA基因上游的DIR调控，称为额外编码(EC)CEBPA。这项建议的总体目标是研究ecCEBPA和谱系特异性DIRS如何引导造血分化。这个项目的基本原理是证明DIR介导的DNA甲基化在造血中的调节。核心假设将通过追求两个具体目标来检验：1)确定ecCEBPA在造血分化中的生物学作用；2)定义DNMT1相互作用的RNA在造血分化中的生物学作用。这项拟议的研究具有创新性，因为我们将剖析DNA甲基化在造血分化中的调节，并揭示控制细胞类型特定甲基化模式的潜在机制。这具有重要意义，因为我们将确定控制造血中DNA甲基化建立的关键表观遗传调控因素；并为实现对这一关键表观遗传标记的基因特异性控制的变革性方法奠定基础。

(PLEASE KEEP IN WORD, DO NOT PDF) Misregulation of hematopoietic genes can result in disruption of the production of functionally specialized blood cells. Abnormal DNA methylation, a key epigenetic signature essential in hematopoiesis, is regarded as the hallmark of most hematological malignancies, including myelodysplastic syndromes (MDS). Unfortunately, the currently approved demethylating agents act indiscriminately on the entire genome and come with a toll of high toxicity and low specificity. Strategies to achieve selective demethylation are therefore needed. The long-term goal of our research is to understand how to develop a highly specific and low toxic approach to correct aberrant DNA methylation in disease states. The central hypothesis is that the establishment of DNA methylation in hematopoiesis is controlled by specialized RNAs, able to bind to the DNA methyltransferase 1 (DNMT1) – DNMT1- interacting RNAs (DiRs). DiRs are widespread and prevent DNA methylation and silencing in a locus-specific manner. Specifically, we have shown that the expression of a master regulator of hematopoietic differentiation, CCAAT/enhancer-binding protein alpha (CEBPA), is regulated by a DiR originated upstream of the CEBPA gene during the S phase, termed extra-coding (ec)CEBPA. The overall objectives of this proposal are to investigate how ecCEBPA and lineage specific DiRs guide hematopoietic differentiation. The rationale for this project is to demonstrate DiR-mediated regulation of DNA methylation in hematopoiesis. The central hypothesis will be tested by pursuing two specific aims: 1) Define the biological role of ecCEBPA in hematopoietic differentiation; and 2) Define the biological role of DNMT1-interacting RNAs in hematopoietic differentiation. The proposed research is innovative because we will dissect the regulation of DNA methylation in hematopoietic differentiation and uncover the mechanisms underlying the control of cell type-specific methylation patterns. It is significant because we will identify key epigenetic regulators governing the establishment of DNA methylation in hematopoiesis; and lay the foundation for a transformative approach to achieve gene-specific control of this critical epigenetic mark.