Molecular characterization of KIR3DL3.
Molecular characterization of KIR3DL3.
复制标题
KIR3DL3 的分子表征。
DOI：
10.1007/s00251-005-0060-7
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发表时间：
2006
期刊：
影响因子：
3.2
通讯作者：
Moffett,Ashley
中科院分区：
文献类型：
--
作者：
Trundley,AnitaE;Hiby,SusanE;Chang,Chiwen;Sharkey,AndrewM;Santourlidis,Simeon;Uhrberg,Markus;Trowsdale,John;Moffett,Ashley
杀伤细胞免疫球蛋白样受体(KIRS)是由自然杀伤(NK)细胞和T细胞亚群表达的一个结构和功能不同的分子家族。人类KIR簇中最具着丝粒的基因是KIR3DL3，这是一种框架基因，存在于所有单倍型中。KIR3DL3只有一个基于酪氨酸的免疫受体抑制基序，在免疫球蛋白结构域和跨膜区之间缺乏编码茎的外显子。我们用逆转录聚合酶链式反应(RT-PCR)检测了KIR3DL3在血液和蜕膜NK细胞中的表达，并使用KIR3DL3特异性单抗ch21进行了蛋白质分析。KIR3DL3mRNA仅在外周血CD56亮细胞亚群和CD56亮NK细胞中表达。CD56brightNK92细胞株也呈阳性反应。定量RT-PCR显示KIR3DL3在女性外周血单个核细胞中的表达高于男性。利用亚硫酸氢盐转化法，我们发现KIR3DL3的启动子发生了强烈的甲基化。去甲基化后可检测到细胞表面蛋白的表达。与其他KIR一样，KIR3DL3具有高度多态，我们在25个无关个体中检测到14个变异。核苷酸替换分散在整个序列中，在跨膜区的开始处有一簇等位基因，在其他KIR中发现连接茎残留物的位置。我们的结论是，KIR3DL3基因不是假基因，而是编码一种在健康个体中不表达的蛋白质。蛋白质的表达可能在某些发育或病理情况下被诱导。
Killer-cell immunoglobulin-like receptors (KIRs) are a structurally and functionally diverse family of molecules expressed by natural killer (NK) cells and T-cell subsets. The most centromeric gene in the human KIR cluster is KIR3DL3, a framework gene that is present in all haplotypes. KIR3DL3 has only one immunoreceptor tyrosine-based inhibitory motif and lacks the exon encoding the stem between the Immunoglobulin domains and the transmembrane region. We have investigated expression of KIR3DL3 in blood and decidual NK cells by reverse transcriptase polymerase chain reaction (RT-PCR) and protein analysis using a KIR3DL3-specific monoclonal antibody, CH21. KIR3DL3 mRNA was only detected in the CD56brightsubset in cells from peripheral blood and in CD56brightdecidual NK cells. The CD56brightNK92 cell line was also positive. Quantitative RT-PCR indicated a trend for higher expression of KIR3DL3 in female peripheral blood mononuclear cells compared to that in male. Using a bisulphite conversion method, we found that the promoter of KIR3DL3 was strongly methylated. Surface protein expression was detectable after demethylation. Like other KIRs, KIR3DL3 is highly polymorphic, and we detected 14 variants in 25 unrelated individuals. Nucleotide substitutions were scattered throughout the sequence, with a cluster of alleles at the start of the transmembrane region at the site where the remnant of the linking stem present in other KIR is found. We conclude that the KIR3DL3 gene is not a pseudogene but encodes a protein that is not expressed in healthy individuals. Protein expression might be induced under certain developmental or pathological situations.