Catalytic roles of RNA methyltransferase DIMT1

核糖体RNA（rRNA）修饰酶是核糖体的组装和功能的重要因素。 核糖体，其失调经常见于人类造血障碍。我们只有 rRNA修饰酶在生理和病理过程中的催化作用的知识 人类造血，虽然一些研究的特点是rRNA修饰的重要性，在这些 流程.我实验室的初步数据（CRISPR筛选）显示，DIMT 1（18 S rRNA Ni·6A-二甲基化（mi·6A）甲基转移酶显著损害造血干细胞活力 祖细胞（HSPC）。DIMT 1在HSPC中高度表达，在分化的HSPC中其表达降低。 血统然而，DIMT 1在人类造血中的分子功能和详细机制仍然存在 难以捉摸。尽管DIMT 1介导的rRNA修饰是高度保守的，但DIMT 1的催化活性仍然存在。 DIMT 1是核糖体生物合成的关键。然而，我们最近的研究结果表明， HSPC的生存力需要DIMT 1的活性，而DIMT 1的催化非依赖性作用很重要 用于18 S rRNA加工和核糖体生物合成。这意味着DIMT 1可能具有必要的作用， 核糖体生物合成中支架与其催化活性分离。此外，我们表明，催化作用 DIMT 1的表达对于范可尼贫血和其他DNA修复相关基因的表达是必不可少的 途径。然而，DIMT 1介导的mi·6A在18 SrRNA中的安装是否以及如何影响细胞活力， HSPC中的DNA修复途径尚不清楚。在这里，我们的目标是了解分子功能， DIMT 1在调节细胞活力和基因表达中的催化作用的机制细节， HSPC。具体而言，目标1将研究DIMT 1作为18 S rRNA甲基转移酶在以下过程中的催化作用： HSPC细胞活力和蛋白质合成。目的2将研究DIMT 1- 在18 S rRNA中介导的m26·6A使用体外真核翻译系统控制翻译延伸。目的 第三部分将研究DIMT 1的结构与功能关系及催化机制。从这些 这些研究将为DIMT 1的催化作用如何影响HSPC细胞活力和HSPC的生物学特性提供新的见解。 范可尼贫血和其他DNA修复途径基因的表达。我们将获得的理解可以是 广泛适用于造血研究和许多其他生物学科。

Ribosome RNA (rRNA) modifying enzymes are important factors in the assembly and function of ribosomes, dysregulation of which is frequently seen in human hematopoietic disorders. We only have limited knowledge of the catalytic role of rRNA modifying enzymes in the physiological and pathological processes of human hematopoiesis, although a few studies characterized the importance of rRNA modifications in these processes. Preliminary data (CRISPR screening) from my laboratory shows that the ablation of DIMT1 (an 18S rRNA Ni·6A-dimethylation (mi·6A) methyltransferase) significantly impairs cell viability of hematopoietic stem progenitor cells (HSPCs). DIMT1 is highly expressed in HSPC, and its expression decreases in the differentiated lineages. However, the molecular function and detailed mechanism of DIMT1 in human hematopoiesis remain elusive. Even though DIMT1-mediated rRNA modifications are highly conserved, the catalytic activity of DIMT1 is dispensable for proper ribosome biogenesis. However, our recent results suggest that the catalytic activity of DIMT1 is required for the viability of HSPCs, while the catalytic-independent role of DIMT1 is important for 18S rRNA processing and ribosome biogenesis. This implies that DIMT1 may have a necessary role as a scaffold in ribosome biogenesis separate from its catalytic activity. Furthermore, we show that the catalytic role of DIMT1 is indispensable for the expression of genes involved in the Fanconi anemia and other DNA repair pathways. However, whether and how DIMT1-mediated mi·6A installation in 18S rRNA influences cell viability and DNA repair pathways in HSPCs are not known. Here, our goal is to understand the molecular function and the mechanistic details of the catalytic role of DIMT1 in the regulation of cell viability and gene expression in HSPCs. Specifically, Aim 1 will investigate the catalytic role of DIMT1 as an 18S rRNA methyltransferase in HSPC cell viability and protein synthesis. Aim 2 will investigate the molecular mechanism by which DIMT1- mediated m26•6A in 18S rRNA controls translation elongation using an in vitro eukaryotic translation system. Aim 3 will investigate the structure-function relationships and catalytic mechanism of DIMT1. Results from these studies will provide novel insights into how the catalytic role of DIMT1 impacts HSPC cell viability and the expression of genes Fanconi anemia and other DNA repair pathways. The understanding we will gain can be broadly applicable to hematopoietic studies and many other biological disciplines.