Physiological function and pathological significance of 4F2 antigen.

4F2抗原的生理功能和病理意义。

• 批准号: 07807025
• 负责人: KAMMA Hiroshi
• 金额: $ 1.41万
• 依托单位: UNIVERSITY OF TSUKUBA
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07807025/
• 关键词: 4F2 antigen; hnRNP A2; hnRNP B1; auto-immune disease; hnRNP B1蛋白; テロメア; NewZealandB; Wマウス; hn RRPA_2; hnRNPB_1; 抗RNP抗体; リン酸化

4F2 antigen is expressed on the membrane of proliferating cells such as cancer cells and activated lymphocytes. Although it is a hetrodimer protein composed of heavy and light chains, the structure of its light chain is still unknown. According to the AAs sequencing analysis, the light chain had a homology to hnRNP A2/B1 (heterogeneous nuclear ribonucleoprotein A2/B1) proteins. The purpose of this study is to clarify the molecular structure and function of 4F2 antigen, especially of its light chin, and its pathological significance.First, in order to identify the light chain, we constructed tagged cDNA of hnRNP A2 and B1 proteins, and transfected them in cultured cells, and demonstrated that only the hnRNP B1 protein was incorporated in the 4F2 antigen. We generated a monoclonal antibody specific to hnRNP B1. The analysis using the antibody indicated that 4F2 light chain was whether modified hnRNP B1 or its another isofrom. Further investigation revealed the followings ; 1) hnRNP B1 protein was post-transitionally modified, that is, phosphorylated, 2) its was expressed on the cell membrane of some kind of cells though it was mainly localized in the nucleus, 3) it was dissociated from the heavy chain under reduced condition. Its expression was cell-specifically regulated and its splcing-isoforms possibly exist in the skin and testis.Because its was reported that the patient of auto-immune disease like SLE had antibodies against hnRNP A2/B1 proteins, we also examined the pahological significance of 4F2 light chain using model mice of autoimmune disease. Anti-hnRNP A2/B1 anitbodies possibly participate in the pathogenesis of renal lesion of Newzealand-B/W mice but not in MRL-lpr/lpr mice. We are carring forward the experiment to analyze it.

4F2抗原表达在增殖细胞的膜上，例如癌细胞和活化的淋巴细胞。虽然它是由重链和轻链组成的异二聚体蛋白，但其轻链的结构仍然未知。根据AAs测序分析，该轻链与hnRNP A2/B1（异质核核糖核蛋白A2/B1）蛋白具有同源性。本研究的目的是阐明4F2抗原的分子结构和功能，特别是其轻下巴的分子结构和功能，及其病理学意义。首先，为了鉴定轻链，我们构建了hnRNP A2和B1蛋白的标记cDNA，并将它们转染到培养细胞中，并证明只有 hnRNP B1 蛋白掺入 4F2 抗原中。我们生成了针对 hnRNP B1 的单克隆抗体。使用抗体的分析表明4F2轻链是否是修饰的hnRNP B1或其另一种异构体。进一步调查发现以下情况； 1) hnRNP B1 蛋白经过转换后修饰，即磷酸化，2) 虽然主要定位于细胞核，但在某种细胞的细胞膜上表达，3) 在还原作用下从重链解离健康）状况。其表达受到细胞特异性调控，其剪接异构体可能存在于皮肤和睾丸中。由于有报道SLE等自身免疫性疾病患者体内存在针对hnRNP A2/B1蛋白的抗体，因此我们还考察了其病理学意义。使用自身免疫性疾病模型小鼠的4F2轻链。抗hnRNP A2/B1抗体可能参与Newzealand-B/W小鼠肾损伤的发病机制，但不参与MRL-lpr/lpr小鼠肾损伤的发病机制。我们正在进行实验进行分析。