Identification of CD16-2, a novel mouse receptor homologous to CD16/FcγRIII
Identification of CD16-2, a novel mouse receptor homologous to CD16/FcγRIII
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DOI：
10.1007/s00251-002-0486-0
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发表时间：
2002-10-01
期刊：
影响因子：
3.2
通讯作者：
Taranin, AV
中科院分区：
文献类型：
--
作者：
Mechetina, LV;Najakshin, AM;Taranin, AV
据认为，小鼠FcgammaRIII是由最近的进化重组产生的，该重组将FcgammaRIII的细胞外结构域与来自祖先FcgammaRIII的跨膜/细胞质区域结合在一起。在这里，我们报道了一个小鼠基因编码跨膜受体的鉴定，该基因可能被视为非啮齿动物CD16/FcgammaRIII的真正同源。新蛋白被命名为CD16-2，在信号肽（60%相同的残基）和细胞外结构域（65%）上与人类FcgammaRIIIA高度相似。虽然两种蛋白在跨膜/细胞质区域的相似性不太明显（54%），但高于人FcgammaRIIIA和小鼠FcgammaRIII之间的相似性（44%）。然而，啮齿动物和人类FcgammaRIII和FCepsilonRI共有的保守跨膜基序LFAVDTGL在CD16-2中有两个替代。CD16-2基因与FcgammaRII和FcgammaRII基因紧密相连，由五个外显子组成。Northern blot分析显示CD16-2在外周血白细胞以及脾脏、胸腺、结肠和肠中表达。RT-PCR在巨噬细胞株J774中表达显著。基于序列比较，我们认为现代哺乳动物低亲和Fc受体是由三个祖先基因的重复复制和/或重组造成的。
It is believed that mouse FcgammaRIII arose by an evolutionarily recent recombination, which brought together the extracellular domains from FcgammaRII with the transmembrane/cytoplasmic region from the ancestor FcgammaRIII. Here, we report identification of a mouse gene encoding a transmembrane receptor that may be regarded as the true ortholog of nonrodent CD16/FcgammaRIII. Designated CD16-2, the novel protein is highly similar to human FcgammaRIIIA in the signal peptide (60% identical residues), and in the extracellular domains (65%). Although the similarity between the two proteins is less conspicuous in the transmembrane/cytoplasmic region (54%), it is higher than between human FcgammaRIIIA and mouse FcgammaRIII (44%). However, the conserved transmembrane motif LFAVDTGL shared by rodent and human FcgammaRIII and FCepsilonRI has two replacements in CD16-2. The CD16-2 gene is tightly linked to the FcgammaRIII and FcgammaRII genes and consists of five exons. Northern blot analysis revealed that CD16-2 is expressed in peripheral blood leukocytes, as well as in spleen, thymus, colon and intestine. RT-PCR showed prominent expression in macrophage cell line J774. Based on sequence comparisons, it is suggested that the modern repertoire of the mammalian low affinity Fc receptors has resulted from repetitive duplications and/or recombinations of three ancestral genes.