NOVEL FUNCTIONS OF RED CELL PROTEINS LU AND LW

描述：（改编自研究者摘要）这是一个修改后的， 重新提交的申请基于红细胞膜 蛋白Lutheran（Lu）和LW在细胞-细胞和细胞-细胞外中起作用 骨髓中的基质相互作用。根据初步结果， 在红细胞生成早期表达并结合α 4 β 1和α v 该申请提出LW可以介导整合素的相互作用， 成红细胞与另一个成红细胞以及与巨噬细胞形成成红细胞 岛状结构。已知Lu糖蛋白结合层粘连蛋白，并且申请人 已经获得证据表明它直到红细胞生成后期才表达。 Lu在细胞表面出现的时间表明， 成红细胞去核或前体细胞从骨髓中释放。 此外，初步结果表明，Lu和LW可能有助于 介导镰状红细胞粘附的镰状细胞病病理生理学 细胞转化为血管内皮细胞为了验证这些假设，申请人 提出：（1）产生缺乏Lu的鼠同源物的敲除小鼠， LW通过同源重组。(2)论鲁的结构功能 和LW通过鉴定Lu和LW参与配体结合的结构域， 采用结构域缺失突变体和定点诱变;开发 封闭抗体和肽，并测试它们对 巨噬细胞-成红细胞和成红细胞相互作用，红系祖细胞 细胞生长和核挤出，使用体外测定和微机械 技术;并通过分析基因敲除小鼠中的红细胞生成， 无效红细胞生成的程度，形成成红细胞岛的能力， 成红细胞去核过程和产生网织红细胞的能力 在应激性红细胞生成过程中(3)检查Lu和LW在镰状细胞中的作用 通过研究输液对血管血流的影响， 具有针对Lu和LW的抗体的转基因/敲除镰状小鼠 其阻断镰状红细胞与内皮细胞的粘附。

DESCRIPTION: (Adapted from investigator's abstract) This is a modified and resubmitted application based on the hypothesis that the erythrocyte membrane proteins Lutheran (Lu) and LW function in cell-cell and cell-extracellular matrix interactions in the bone marrow. Based on preliminary results that LW is expressed early in erythropoiesis and binds to alpha4beta1 and alphav integrins, the application proposes that LW may mediate interactions of erythroblasts with one another and with macrophages to form the erythroblastic island structure. Lu glycoprotein is known to bind laminin and the applicant has obtained evidence that it is not expressed until late in erythropoiesis. The timing of the appearance of Lu on the cell surface suggests a role in erythroblast enucleation or release of precursors from the marrow. Additionally, preliminary results indicate that Lu and LW may contribute to the pathophysiology of sickle cell disease by mediating the adhesion of sickle red cells to vascular endothelial cells. To test these hypotheses the applicant proposes to: (1) Generate knockout mice lacking the murine homologues of Lu and LW by homologous recombination. (2) Characterize the structure-function of Lu and LW by identifying the domains of Lu and LW involved in ligand binding and employing domain-deletion mutants and site-directed mutagenesis; developing blocking antibodies and peptides and testing their effects on macrophage-erythroblast and erythroblast interactions, erythroid progenitor cell growth, and nuclear extrusion using in vitro assays and micromechanical techniques; and by analyzing erythropoiesis in the knockout mice including the degree of ineffective erythropoiesis, capacity to form erythroblastic islands, process of erythroblast enucleation, and ability to generate reticulocytes during stress erythropoiesis. (3) Examine roles of Lu and LW in sickle cell disease by studying the effect on vascular blood flow of infusing transgenic/knockout sickle mice with antibodies directed against Lu and LW which block adhesion of sickle red cells to endothelial cells.