Paired Ig-like receptor homologs in birds and mammals share a common ancestor with mammalian Fc receptors
Paired Ig-like receptor homologs in birds and mammals share a common ancestor with mammalian Fc receptors
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DOI：
10.1073/pnas.230442897
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发表时间：
2000-11-21
影响因子：
11.1
通讯作者：
Cooper, MD
中科院分区：
文献类型：
--
作者：
Dennis, G;Kubagawa, H;Cooper, MD
在哺乳动物中已经描述了可以相互调节细胞激活的配对 Ig 样受体 (PIR)。在本研究中，我们在表达序列标签数据库中搜索了 PIR 亲属，以鉴定鸡表达序列标签，预测其与小鼠 PIR 具有约 25% 的氨基酸同一性。 cDNA 末端快速扩增 (RACE) - 使用鸡脾 cDNA 作为模板表达序列标签序列的 PCR 延伸产生了两种不同的 cDNA，其序列分析预测了具有相关胞外 Ig 样结构域的蛋白质产物。鸡 Ig 样受体 (CHIR)-A 的特征在于其跨膜片段带有带正电荷的组氨酸残基和短胞质尾部，从而将 CHIR-A 确定为候选激活受体。相反，CHIR-B 的特征在于其非极性跨膜片段和细胞质尾部具有两个基于免疫受体酪氨酸的抑制基序，表明其可能充当抑制性受体。使用 CHIR 氨基酸序列寻找其他 PIR 亲属导致将哺乳动物 Fc 受体识别为远缘相关基因。基于氨基酸序列和三维蛋白质结构的比较分析为PIR和Fc受体基因家族的共同祖先提供了分子证据。
Paired Ig-like receptors (PIR) that can reciprocally modulate cellular activation have been described in mammals. In the present study, we searched expressed sequence tag databases for PIR relatives to identify chicken expressed sequence tags predictive of approximate to 25% amino acid identity to mouse PIR. Rapid amplification of cDNA ends (RACE)-PCR extension of expressed sequence-tag sequences using chicken splenic cDNA as a template yielded two distinct cDNAs, the sequence analysis of which predicted protein products with related extracellular Ig-like domains. Chicken Ig-like receptor (CHIR)-A was characterized by its transmembrane segment with a positively charged histidine residue and short cytoplasmic tail, thereby identifying CHIR-A as a candidate-activating receptor. Conversely, CHIR-B was characterized by its nonpolar transmembrane segment and cytoplasmic tail with two immunoreceptor tyrosine-based inhibitory motifs, indicating that it may serve as an inhibitory receptor. The use of CHIR amino acid sequences in a search for other PIR relatives led to the recognition of mammalian Fc receptors as distantly related genes. Comparative analyses based on amino acid sequences and three-dimensional protein structures provided molecular evidence for common ancestry of the PIR and Fc receptor gene families.