MECHANISTIC STUDIES OF DOT1L FUNCTION IN EMBRYONIC ERYTHROPOIESIS

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 精确调节的基因表达对于正常细胞功能以及各种正常的细胞功能是至关重要的。 哺乳动物的发育过程。组蛋白甲基化状态已成为一个重要的决定因素 基因位点转录活性的影响。DOT 1 L（Distruptor of Telomere Silencing 1-Like）组蛋白H3赖氨酸 79（H3 K79）甲基转移酶参与了几种不同的生物学过程，包括阳性反应。 转录调控。我们从基因陷阱靶向的胚胎干细胞（ES）中产生了Dot 1 L基因敲除小鼠。 细胞Dot 1 L基因敲除的小鼠比野生型胚胎发育更慢，并在E10.5和E13.5之间死亡。 E10.5胚胎表现出明显的贫血，尤其是在卵黄囊的小血管中， 最早的造血过程此外，来自这些小鼠的造血祖细胞显示出缺陷生长 对红细胞生长因子的反应。GATA 2是一种对早期红细胞生成至关重要的转录因子， 在Dot 1 L缺陷型造血祖细胞中，PU.1的表达显著降低，而PU.1是一种转录因子， 抑制红细胞生成和促进骨髓生成的因子显著增加。这些数据 这表明DOT 1 L依赖性H3 K79甲基化在分化过程中充当分化开关的模型， 早期造血，调节GATA 2和PU.1转录的稳态水平，从而控制 适当数量的循环红细胞和髓细胞。 这项研究的目的是帮助我们了解这一作用的总体科学目标， 甲基转移酶在胚胎红细胞生成中的作用我们设计了一个特定的目标来检查该机制 DOT 1 L可能通过该途径调节参与细胞命运特化的关键基因的表达， 过程这项研究的完成将为红细胞生成的表观遗传调控提供新的见解， 并使我们能够为今后在这一一般调查领域的工作奠定坚实的基础。 虽然拟议工作的范围远非全面，但我们有信心， 在规定的时间内提供数据。这些数据将大大有助于我们努力获得长期， 为这项工作提供校外资金。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Precisely tuned gene expression is critical for normal cellular functions as well as a variety of normal mammalian developmental processes. Histone methylation status has emerged as an important determinant of gene locus transcriptional activity. The DOT1L (Disruptor of Telomere Silencing 1-Like) histone H3 lysine- 79 (H3K79) methyltransferase has been implicated in several distinct biological processes, including positive regulation of transcription. We generated Dot1L-null mice from gene trap-targeted embryonic stem (ES) cells. Dot1L-null mice developed more slowly than wild-type embryos and died between E10.5 and E13.5. E10.5 embryos displayed a striking anemia, especially apparent in the small vessels of the yolk sac, the site of most early hematopoiesis. Further, hematopoietic progenitors from these mice displayed defective growth in response to erythroid growth factors. GATA2, a transcription factor critical for early erythropoiesis, was significantly reduced in Dot1L-deficient hematopoietic progenitors while expression of PU.1, a transcription factor that inhibits erythropoiesis and promotes myelopoiesis, was significantly increased. These data suggest a model whereby DOT1L-dependent H3K79 methylation serves as a differentiation switch during early hematopoiesis, regulating steady-state levels of GATA2 and PU.1 transcription and thus controlling the appropriate numbers of circulating erythroid and myeloid cells. This study is designed to contribute to our overall scientific goal of understanding the role for this methyltransferase in embryonic erythropoiesis. We have devised a specfic aim to examine the mechanism by which DOT1L might regulate the expression of critical genes involved in cell-fate specification during this process. The completion of this study will provide novel insight into epigenetic regulation of erythropoiesis as well as enable us to produce a substantial foundation for future work in this general area of investigation. Although the scope of the proposed work is far from comprehensive, we are confident that we will obtain data within the time allotted. These data will significantly contribute to our efforts at obtaining long-term, extramural funding for this work.