Contributions of the H3K27 demethylases UTX (KDM6A) and UTY (KDM6C) to hematopoiesis and sex specific differences in gene expression

H3K27 去甲基酶 UTX (KDM6A) 和 UTY (KDM6C) 对造血和基因表达性别特异性差异的贡献

• 批准号: 432655278
• 负责人: Professor Dr. Konstantinos Anastassiadis
• 金额: --
• 依托单位: Biotechnologisches Zentrum (Biotec)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/432655278?language=en
• 关键词: Contributions; H3K27; demethylases; UTX; KDM6A

Accumulating evidence indicates that epigenetic regulators including histone methyltransferases and demethylases contribute to normal hematopoiesis. Using conditional mutagenesis in mice we and others have shown that the histone 3 lysine 27 (H3K27) demethylase UTX (KDM6A), located on the X-chromosome, is required for embryonic development and hematopoiesis in adult female mice. Utx is one of the few genes that escape X-chromosome inactivation and so females express both Utx alleles. Notably, a Utx paralog, Uty, is present on the Y-chromosome so males express the hemizygous pair Utx/Uty. Notably, it has been reported that UTY has significantly less demethylase activity than UTX, which has potential implications for sex-specific differences. Other differences between UTX and UTY include significantly higher UTX mutation frequencies in cancers. We have also observed a heterozygous phenotype in Utx-mutant/Uty-wt (male) embryos that is not apparent in Utx-mutant/Utx-wt (female) or Uty-mutant/Utx-wt (male) embryos, indicating that UTY does not substitute for all UTX functions during mouse development. The difference in demethylase activities could account for these UTX-UTY differences, however UTX functions that do not require demethylation have been reported. To address the differences between UTX and UTY, we will investigate their roles in murine HSPC homeostasis using conditional mutagenesis of Utx and Uty loxP alleles combined with transplantation experiments, transcriptome analyses and target gene identification. To evaluate the contributions of demethylase dependent versus independent functions, we will employ an in vitro hematopoietic differentiation assay from conditional Utx and Uty mESCs using BAC transgenes point mutated or not for demethylase activity, potentially supported by similar experiments with immortalized HSPCs. Following the recent prediction that the UTX/UTY protein complexes are dimeric, we will also evaluate whether male ESCs contain three types of complex (UTY/UTY; UTY/UTX and UTX/UTX) as opposed to one type in female ESCs (UTX/UTX) to determine if this could also be a source of sex specific differences. This research proposal will deliver new insights into UTX/UTY epigenetic regulation in general and murine HSPC homeostasis in particular. It will build upon and complement our ongoing analyses of the histone 3 lysine methylation circuitry in hematopoiesis and may uncover a molecular basis for sex specific differences.

越来越多的证据表明，表观遗传调节因子包括组蛋白甲基转移酶和脱甲基酶有助于正常的造血。我们和其他人在小鼠中使用条件诱变已经表明，位于X染色体上的组蛋白3赖氨酸27（H3 K27）脱甲基酶UTX（KDM 6A）是成年雌性小鼠胚胎发育和造血所必需的。Utx是少数几个逃脱X染色体失活的基因之一，因此女性表达两个Utx等位基因。值得注意的是，在Y染色体上存在一个Utx paramount，Uty，因此雄性表达半合子对Utx/Uty。值得注意的是，据报道，UTY的脱甲基酶活性明显低于UTX，这对性别特异性差异有潜在的影响。UTX和UTY之间的其他差异包括在癌症中显著更高的UTX突变频率。我们还观察到Utx突变体/Uty-wt（雄性）胚胎中的杂合表型在Utx突变体/Utx-wt（雌性）或Uty-突变体/Utx-wt（雄性）胚胎中不明显，表明UTY在小鼠发育期间不能替代所有UTX功能。去甲基化酶活性的差异可以解释这些UTX-UTY差异，但是已经报道了不需要去甲基化的UTX功能。为了解决UTX和UTY之间的差异，我们将使用Utx和Uty loxP等位基因的条件诱变结合移植实验、转录组分析和靶基因鉴定来研究它们在小鼠HSPC稳态中的作用。为了评估脱甲基酶依赖性功能与独立功能的贡献，我们将采用条件性Utx和Uty mESC的体外造血分化测定，其使用针对脱甲基酶活性点突变或未点突变的BAC转基因，这可能得到永生化HSPC的类似实验的支持。根据最近的预测，UTX/UTY蛋白复合物是二聚体，我们还将评估男性ESC是否含有三种类型的复合物（UTY/UTY; UTY/UTX和UTX/UTX），而不是女性ESC中的一种类型（UTX/UTX），以确定这是否也可能是性别特异性差异的来源。这项研究计划将为UTX/UTY表观遗传调控提供新的见解，特别是小鼠HSPC稳态。它将建立和补充我们正在进行的分析组蛋白3赖氨酸甲基化电路在造血，并可能揭示性别特异性差异的分子基础。