NOVEL PAIR OF IMMUNOGLOBULIN LIKE RECEPTORS IN MICE

小鼠体内的一对新型免疫球蛋白样受体

• 批准号: 2887625
• 负责人: Hiromi Kubagawa
• 金额: $ 24.91万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2887625
• 关键词: B lymphocyte; antibody receptor; antireceptor antibody; chimeric proteins; crosslink; gene targeting; laboratory mouse; laboratory rat; ligands; macrophage; monoclonal antibody; nucleic acid sequence; protein localization; protein structure function; receptor expression; tissue /cell culture; transfection

A novel paired immunoglobulin-like receptor (PIR) gene family in mice is the focus of these studies. Sequences of the prototypic full length cDNA clones, PIR-A and PIR-B, predict type I transmembrane proteins of 75 and 87 kD with similar ectodomains, but distinctive transmembrane and cytoplasmic regions. The predicted PIR-A protein has a relatively short cytoplasmic tail and a charged Arg residue in the transmembrane region, suggesting association with an additional transmembrane protein(s) to form a signal transducing unit. In contrast, the PIR-B protein has a nonpolar transmembrane region and a relatively long cytoplasmic tail with two consensus immunoreceptor tyrosine-based inhibitory motifs (ITIM). The predicted peptide sequences are invariant in five consecutive PIR-B cDNA clones, but differ for all seven PIR-A type cDNA clones. PIR-A and PIR-B expression appears to be restricted to B lymphocytes and myeloid cells, wherein both genes are expressed simultaneously. The present studies are designed to test the hypothesis that the PIR-A and PIR-B cDNAs encode receptor proteins with related ligand-binding specificity, but different intracellular signaling properties so that the PIR-A molecular complex may have activating potential, while PIR-B may have inhibitory potential via its ITIM-like motifs. The first experiments are designed to produce monoclonal antibodies against common and distinctive epitopes on the PIR-A and PIR- B molecules and to use these antibodies to determine their cellular distribution and relative expression levels, their structure and unit composition, and the effects of PIR-crosslinkage on B cell and macrophage responses. The second experiments will examine the functional potential of the ITIM-like motifs in the PIR-B molecules. The third set of experiments is designed to isolate and sequence genomic PIR-A and PIR-B clones (i) to determine the genetic basis for the sequence diversity of the PIR-A genes and (ii) to disrupt the single copy PIR-B gene in embryonic stem cells to generate PIR-B knockout mice with unbalanced PIR-A activity. The fourth set of experiments will examine PIR-A transcripts in representative macrophage and B cell lines to determine whether they express single or multiple receptor members. The final experiments are designed to identify the ligand(s) for these PIR molecules. These studies may reveal an important regulatory role for the PIR-A and PIR-B receptors in humoral, inflammatory and allergic responses.

小鼠中的一种新型成对的免疫球蛋白样受体（PIR）基因家族 是这些研究的重点。 原型全长的序列 cDNA克隆，PIR-A和PIR-B，预测I型跨膜蛋白 75和87 kd具有相似的外域，但具有独特的跨膜和 细胞质区域。 预测的PIR-A蛋白具有相对较短的 跨膜区域的细胞质尾巴和带电的ARG残留物， 暗示与额外的跨膜蛋白（s）的关联 形成信号传递单元。 相反，PIR-B蛋白具有 非极性跨膜区域和相对较长的细胞质尾巴 具有两个共识免疫受体酪氨酸抑制基序 （itim）。 预测的肽序列在五个 连续的PIR-B cDNA克隆，但在所有七个PIR-A型cDNA中有所不同 克隆。 PIR-A和PIR-B表达似乎仅限于B 淋巴细胞和髓样细胞，其中两个基因均表达 同时地。 目前的研究旨在检验假设 PIR-A和PIR-B cDNA编码具有相关的受体蛋白 配体结合特异性，但细胞内信号传导不同 属性使得PIR-A分子复合物可能具有激活 潜力，而PIR-B可能通过其ITIM样具有抑制潜力 主题。 第一个实验旨在产生单克隆 对PIR-A和PIR-的共同表位和独特表位的抗体 B分子并使用这些抗体来确定其细胞 分布和相对表达水平，其结构和单位 组成，以及pir-crosslinkage对B细胞和 巨噬细胞反应。 第二个实验将检查 PIR-B分子中ITIM样基序的功能潜力。 第三组实验旨在分离和序列基因组 PIR-A和PIR-B克隆（i）确定遗传基础 PIR-A基因的序列多样性和（ii）破坏单个基因 在胚胎干细胞中复制PIR-B基因以产生PIR-B基因敲除小鼠 具有不平衡的PIR-A活性。 第四组实验将 检查代表性巨噬细胞和B细胞系中的PIR-A转录本 确定它们是表达单个受体还是多个受体 成员。 最终实验旨在识别配体 对于这些PIR分子。 这些研究可能揭示了一个重要的 PIR-A和PIR-B受体在体液中的调节作用， 炎症和过敏反应。