Control of Erythroid Differentiation by Transcription Elongation

通过转录延伸控制红系分化

基本信息

批准号：
8205185
负责人：
LEONARD Ira ZON
金额：
$ 42.91万
依托单位：
BOSTON CHILDREN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-08-15 至 2016-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8205185
关键词：
Anemia Animal Model Binding Blood Bone Marrow Cells Chromatin Complex Couples DNA Polymerase II DNA-Binding Proteins Defect Development Developmental Biology Disease Ensure Erythrocytes Erythroid Erythroid Cells Erythropoiesis Fishes GATA1 gene Gene Expression Gene Targeting Genes Genetic Genetic Transcription Grant Hematological Disease Hematopoiesis Hematopoietic Human Hypochromic anemia Instruction Iron Knock-out Knockout Mice MEL Gene Membrane Modeling Monitor Mus Mutant Strains Mice Myelogenous Myelopoiesis Nuclear Orthologous Gene Phenotype Phosphotransferases Positive Transcriptional Elongation Factor B Process Proteins RNA RNA Binding RNA Sequences Regulation Role Sickle Cell Anemia Signal Transduction Small RNA Stem cells T-cell acute lymphocytic leukemia 1 protein Technology Thalassemia Tissues Transcript Transcription Elongation Vertebrates Zebrafish erythroid differentiation humoral immunity deficiency knock-down membrane assembly mutant novel overexpression progenitor research study sensor transcription factor

项目摘要

PROJECT SUMMARY (See instructions): Erythroid differenfiafion is controlled at the transcripfional level by the cell-specific DNA-binding proteins SCL and GATA1. Using zebrafish genefics, we found a new differentiation checkpoint in erythroid cells that likely ensures successful maturafion. We undertook the flrst recessive suppressor screen in vertebrates to find a novel mutant that can recover erythropoiesis in the background ofthe anemic zebrafish mutant moonshine. Moonshine encodes the zebrafish ortholog of transcripfional intermediary factor 1 gamma (TIFly), and the first suppressor of moonshine encoded cdc73, a chromatin factor involved in transcripfion elongafion. Moonshine mutants have paused blood-specific RNA transcripts, and cdc73 deficiency allows elongafion to occur and rescues erythroid gene expression. TIFly binds to the SCL transcription factor complex and PTEFb, the kinase that phosphorylates pol II and regulates the elongation of RNA transcripts. We have examined the hematopoiefic phenotype of a condifional mouse knockout for TIFly. Bone marrow erythropoiesis is defective, myelopoiesis is increased, and there is a severe deficiency of B cells. We plan to evaluate transcripfion elongation in erythroid and myeloid progenitors of this mouse mutant. Transplantafion experiments are planned to evaluate a putative stem cell funcfional defect and the autonomy ofthe red cell defect. We will establish if the differenfiafion checkpoint is acfivated in diseases such as hypochromic anemias or membrane assembly defects. HEXIM 1 was originally identified as a gene induced during MEL differenfiation, and it complexes with other proteins and 7SK RNA to regulate P-TEFb activity. We hypothesize that HEXIM complexes could serve as a sensor of erythroid differenfiafion. We plan to define the binding partners of HEXIM in erythroid cells, and to evaluate the funcfion ofthe HEXIM complex subunits during erythropoiesis in fish and mice. The function ofthe 7SK RNA component of HEXIM will be invesfigated. A new sequencing technology will determine if other small RNAs are bound to the HEXIM complex. The regulation of transcription elongation in the differentiation checkpoint of erythroid cells wili be relevant to diseases such as thalassemia, sickle cell anemia, iron deflciency, and membrane defects.

项目摘要（参见说明）：红细胞分化在转录水平上由细胞特异性 DNA 结合蛋白 SCL 控制和GATA1。利用斑马鱼遗传学，我们在红细胞中发现了一个新的分化检查点，这可能是确保成功成熟。我们在脊椎动物中进行了首次隐性抑制筛选，以找到可以在贫血斑马鱼突变体月光背景下恢复红细胞生成的新型突变体。 Moonshine 编码转录中间因子 1 gamma (TIFly) 的斑马鱼直系同源物，并且 Moonshine 的第一个抑制因子编码 cdc73，一种参与转录延伸的染色质因子。 Moonshine 突变体已暂停血液特异性 RNA 转录，并且 cdc73 缺陷导致延伸发生并挽救红细胞基因表达。 TIFly 与 SCL 转录因子复合物和 PTEFb 结合，磷酸化 pol II 并调节 RNA 转录本延伸的激酶。我们有检查了 TIFly 条件性小鼠基因敲除的造血表型。骨髓红细胞生成有缺陷，骨髓生成增加，B细胞严重缺乏。我们计划评估该小鼠突变体的红细胞和骨髓祖细胞的转录延伸。移植计划进行实验来评估假定的干细胞功能缺陷和红细胞的自主性缺点。我们将确定分化检查点是否在低色素等疾病中被激活贫血或膜组装缺陷。 HEXIM 1 最初被鉴定为 MEL 期间诱导的基因分化，并与其他蛋白质和 7SK RNA 复合以调节 P-TEFb 活性。我们假设 HEXIM 复合物可以作为红细胞分化的传感器。我们计划定义红细胞中 HEXIM 的结合伴侣，并评估 HEXIM 复合亚基的功能在鱼和小鼠的红细胞生成过程中。 HEXIM 的 7SK RNA 成分的功能是调查了。一种新的测序技术将确定其他小 RNA 是否与 HEXIM 结合复杂的。红系细胞分化检查点转录延伸的调节与地中海贫血、镰状细胞性贫血、缺铁和细胞膜缺陷等疾病有关。