Characterization and expression analysis of an interleukin-7 homologue in the Japanese pufferfish, Takifugu rubripes
Characterization and expression analysis of an interleukin-7 homologue in the Japanese pufferfish, Takifugu rubripes
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DOI：
10.1111/j.1742-4658.2008.06281.x
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发表时间：
2008-03-01
期刊：
影响因子：
5.4
通讯作者：
Sakai, Masahiro
中科院分区：
文献类型：
--
作者：
Kono, Tomoya;Bird, Steve;Sakai, Masahiro
一种白细胞介素-7 （IL-7）基因在日本河豚Takifugu rubripes （Fugu）中被克隆并测序，首次为硬鱼中存在IL-7提供了确凿的证据。IL-7 cDNA由1438 bp组成，其中5'-UTR为117 bp， 3'-UTR为826 bp，包含两个mRNA不稳定基序，ORF为498 bp，可翻译成166个氨基酸残基的肽段。河豚IL-7肽含有19个氨基酸残基的预测信号肽和IL-7/9家族特征（Arg140-Val149）。河豚IL-7与其他已知IL-2家族成员的同源性分析显示，河豚IL-7与已知哺乳动物IL-7和IL-21分子有一定的相似性；系统进化树分析显示，河豚IL-7与鸡和哺乳动物IL-7和哺乳动物IL-9聚集在一起，远离其他IL-2家族成员（IL-2、IL-4、IL-15和IL-21）。河豚IL-7基因的结构与小鼠相同，由5个外显子和4个内含子组成，但与人类基因由6个外显子和5个内含子组成不同。河豚基因组与人类基因组的比较表明，在IL-7基因周围存在一定的同质性，蛋白激酶抑制剂α和8号染色体orf70 （C8orf70）基因均存在，且IL-7和C8orf70具有相同的转录取向。河豚IL-7基因在头肾、脾、肝、肠、鳃和肌肉等未受刺激的组织中表达。用脂多糖、多肌苷多胞酸或植物血凝素刺激头肾细胞可增加这种表达。在河豚中发现的IL-7将使将来对鱼类免疫反应进行更完整的分析。
An interleukin-7 (IL-7) gene has been cloned and sequenced within the Japanese pufferfish, Takifugu rubripes (Fugu), providing the first conclusive evidence for the existence of IL-7 in teleosts. The IL-7 cDNA was composed of 1438 bp, with a 117 bp 5'-UTR, an 826 bp 3'-UTR containing two mRNA instability motifs, and a 498 bp ORF which translates into a peptide of 166 amino acid residues. The Fugu IL-7 peptide contained a predicted signal peptide of 19 amino acid residues and the IL-7/9 family signature (Arg140-Val149). Homology analysis of Fugu IL-7 with other known IL-2 family members showed some similarity to the known mammalian IL-7 and Fugu IL-21 molecules, and phylogenetic tree analysis showed that the Fugu IL-7 clustered with the chicken and mammalian IL-7 and mammalian IL-9, away from other IL-2 family members (IL-2, IL-4, IL-15 and IL-21). The organization of the Fugu IL-7 gene was the same as in mouse, and consisted of five exons and four introns, but differed from the human gene, which is composed of six exons and five introns. Comparison of the Fugu and human genomes showed that some synteny existed around the IL-7 gene, with the presence of both the protein kinase inhibitor-alpha and chromosome 8 ORF 70 (C8orf70) genes, with IL-7 and C8orf70 having the same transcriptional orientation. The Fugu IL-7 gene was expressed within unstimulated tissues, such as the head kidney, spleen, liver, intestine, gill and muscle. Stimulation of head kidney cells with lipopolysaccharide, polyinosinic polycytidylic acid or phytohaemagglutinin increased this expression. This discovery of IL-7 in Fugu will allow a more complete analysis of fish immune responses in the future.