Understanding the role of cell-cycle specific RNAs in hematopoiesis

（请保持文字，不要PDF） 造血基因的失调可导致功能特化血细胞的产生中断。异常DNA甲基化是造血过程中重要的表观遗传标记，被认为是包括骨髓增生异常综合征（MDS）在内的大多数恶性血液病的标志。不幸的是，目前批准的去甲基化剂不加选择地作用于整个基因组，并且具有高毒性和低特异性。因此，需要实现选择性去甲基化的策略。我们研究的长期目标是了解如何开发一种高度特异性和低毒性的方法来纠正疾病状态下的异常DNA甲基化。核心假设是，造血中DNA甲基化的建立是由能够与DNA甲基转移酶1（DNMT 1）-DNMT 1相互作用RNA（DiR）结合的专门RNA控制的。DiR广泛存在，并以基因座特异性方式防止DNA甲基化和沉默。具体而言，我们已经表明，造血分化的主调节因子，CCAAT/增强子结合蛋白α（CEBPA）的表达，是由一个DiR起源于CEBPA基因的上游在S期，称为编码外（EC）CEBPA。本提案的总体目标是研究ecCEBPA和谱系特异性DiR如何指导造血分化。该项目的基本原理是证明DiR介导的造血中DNA甲基化的调节。中心假设将通过追求两个特定目标进行测试：1）定义ecCEBPA在造血分化中的生物学作用; 2）定义DNMT 1相互作用RNA在造血分化中的生物学作用。这项研究是创新的，因为我们将剖析造血分化中DNA甲基化的调控，并揭示控制细胞类型特异性甲基化模式的机制。这是重要的，因为我们将确定关键的表观遗传调节因子，控制造血中DNA甲基化的建立;并为实现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.