Novel Erythroid Cell Membrane Protein

新型红细胞膜蛋白

• 批准号: 7595979
• 负责人: Emery H Bresnick
• 金额: $ 22.28万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7595979
• 关键词: Adult; Anemia; Antibodies; Biochemical; Bioinformatics; Biological; Biological Process; Bone Marrow; Cell Membrane Proteins; Cell membrane; Cell physiology; Cells; Cellular biology; Development; Embryo; Embryonic Development; Epitopes; Erythroblasts; Erythrocytes; Erythroid; Erythroid Cells; Erythroid Progenitor Cells; Erythropoiesis; Erythropoietin; Exhibits; Fetal Liver; Gene Targeting; Genes; Genetic; Genetic Transcription; Hematopoiesis; Hematopoietic stem cells; Hemoglobin concentration result; Immunoglobulins; In Situ; In Situ Hybridization; Integral Membrane Protein; Island; Kidney Diseases; Knockout Mice; Lymphopoiesis; Malignant Neoplasms; Megakaryocytes; Membrane Proteins; Messenger RNA; Minor; Modeling; Molecular; Mus; Patients; Pattern; Protein Family; Proteins; Reagent; Role; Safety; Signal Transduction; Site; Testing; Therapeutic Agents; Zebrafish; base; eosinophil; erythroid differentiation; extracellular; human GATA1 protein; intercellular cell adhesion molecule; intercellular communication; interest; knock-down; loss of function; macrophage; mast cell; member; novel; novel strategies; paralogous gene; prospective; protein structure function; public health relevance; receptor; transcription factor

DESCRIPTION (provided by applicant): While erythropoietin (Epo) is commonly used to treat anemia in patients with cancer and kidney disease, recent studies have raised major safety concerns. There is great interest in developing new strategies to modulate erythropoiesis, and in this regard, we have been analyzing GATA transcription factor function. GATA-2 regulates the proliferation/survival of hematopoietic stem cells (HSCs), whereas GATA-1 promotes the differentiation of erythroid, megakaryocyte, eosinophil, and mast cells. Analysis of GATA-1 function in GATA-1-null erythroid precursor cells revealed a novel target gene, mFam55B. GATA-1 directly activates mFam55B transcription, and mFam55B expression is highly restricted to definitive erythroblasts in murine fetal liver and adult bone marrow. Although mFam55B has minor sequence similarity to Intercellular Cell Adhesion Molecule-4 (ICAM4), which is implicated in formation of functionally important erythroblastic islands, the bulk of mFam55B sequence does not resemble ICAM4 or other known proteins. mFam55B appears to be a Type II membrane protein, whereas ICAMs are Type I membrane proteins. We discovered four mammalian mFam55B-related genes, which have not been described, but only mFam55B is GATA-1-regulated. mFam55B is predicted to have a transmembrane helix and two extracellular immunoglobulin (Ig)-like repeats. mFam55B and its paralogs define a new protein family, and we hypothesize that mFam55B is an erythroid precursor membrane protein with important functions in erythroid cell biology. The following aims describe pilot/exploratory studies to develop reagents/models to define mFam55B function and to investigate the role of mFam55B in the formation of erythroblastic islands. Aim 1 - To determine whether mFam55B is a GATA-1-regulated transmembrane protein in erythroid precursor cells. We hypothesize that mFam55B is a transmembrane protein in erythroid precursor cells that functions via intercellular signaling. We will test whether GATA-1 regulates endogenous mFam55B levels, whether mFam55B exhibits predominant plasma membrane localization, and whether it resides in erythroblastic islands. Aim 2 - To investigate biological functions of mFam55B via loss-of-function studies in zebrafish and mice. We identified five novel zebrafish genes with significant sequence similarity to mFam55B. Knocking down one of these genes yielded severe anemia. We will knockdown the mFam55B-related genes to determine if they regulate erythropoiesis, will define their expression patterns, and will test whether their expression is GATA-1-dependent. We will also generate a mFam55B-null mouse to begin to dissect the role of mFam55B in erythroid cell function and/or erythropoiesis. PUBLIC HEALTH RELEVANCE: This project focuses on analyzing a novel GATA-1 regulated protein, mFam55B, that we discovered, which is predicted to be a single-pass transmembrane protein on erythroid precursor cells and to represent the founding member of a new protein family. As GATA-1 is a fundamental regulator of erythropoiesis, we hypothesize that mFam55B has important functions to regulate red blood cell development and/or erythroid precursor cell function. The proposed pilot/exploratory studies therefore have potential to yield high impact findings of relevance to novel strategies to stimulate red blood cell development, to elucidating how erythroid precursor cell function is altered in pathophysiological states, and to unraveling fundamental aspects of protein structure/function.

描述（由申请人提供）：虽然促红细胞生成素（EPO）通常用于治疗癌症和肾脏疾病患者的贫血，但最近的研究引起了主要的安全问题。人们对制定新策略来调节红细胞生成有很大的兴趣，在这方面，我们一直在分析GATA转录因子功能。 GATA-2调节造血干细胞（HSC）的增殖/存活，而GATA-1促进了红细胞，巨核细胞，嗜酸性粒细胞和肥大细胞的分化。 GATA-1无效的红细胞前体细胞中GATA-1功能的分析揭示了一种新型的靶基因MFAM55B。 GATA-1直接激活MFAM55B转录，MFAM55B表达高度限于在鼠胎儿肝脏和成年骨髓中的确定性红细胞。尽管MFAM55B与细胞间细胞粘附分子-4（ICAM4）具有较小的序列相似性，该分子与功能重要重要的红母细胞岛的形成有关，但MFAM55B序列的大部分与ICAM4或其他已知蛋白质不相似。 MFAM55B似乎是II型膜蛋白，而ICAM是I型膜蛋白。我们发现了四个尚未描述的哺乳动物MFAM55B相关基因，但只有MFAM55B进行了GATA-1调节。预测MFAM55B具有跨膜螺旋和两个细胞外免疫球蛋白（Ig）类似重复序列。 MFAM55B及其旁系同源物定义了一种新的蛋白质家族，我们假设MFAM55B是一种红细胞前体膜蛋白，在红细胞细胞生物学中具有重要功能。以下目的描述了开发试剂/模型来定义MFAM55B功能并研究MFAM55B在形成红细胞群岛中的作用的试验/探索性研究。 AIM 1-确定MFAM55B是否是红细胞前体细胞中GATA-1调节的跨膜蛋白。我们假设MFAM55B是通过细胞间信号传导起作用的红细胞前体细胞中的跨膜蛋白。我们将测试GATA-1是否调节内源性MFAM55B水平，MFAM55B是否表现出主要的质膜定位，以及它是否驻留在红细胞岛。 AIM 2-通过斑马鱼和小鼠的功能丧失研究来研究MFAM55B的生物学功能。我们确定了五个与MFAM55B显着序列相似性的新型斑马鱼基因。击倒这些基因之一会产生严重的贫血。我们将敲除MFAM55B相关的基因，以确定它们是否调节红细胞生成，将定义其表达模式，并将测试其表达是否依赖于GATA-1依赖性。我们还将生成MFAM55B无效的小鼠，以开始剖析MFAM55B在红细胞功能和/或促红细胞生成中的作用。公共卫生相关性：该项目的重点是分析我们发现的新型GATA-1调节蛋白MFAM55B，该蛋白被认为是红斑前体细胞上的单次跨膜蛋白，并代表新蛋白质家族的创始成员。由于GATA-1是红细胞生成的基本调节剂，因此我们假设MFAM55B具有调节红细胞发育和/或红细胞前体细胞功能的重要功能。因此，拟议的试点/探索性研究可能会产生与新型策略相关的高影响结果，以刺激红细胞发育，以阐明病理生理状态中红细胞前体细胞功能的改变，并揭示蛋白质结构/功能的基本方面。