Wan Xiang, Chen Xinhua
Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China.
Vet Immunol Immunopathol. 2008 Jul 15;124(1-2):99-106. doi: 10.1016/j.vetimm.2008.01.004. Epub 2008 Jan 16.
In human cells, interferon-inducible transmembrane protein 1 (IFITM1) is a component of protein complexes involved in homotypic adhesion and the transduction of antiproliferative signals. Here, we reported the cloning of an IFITM1 homologue from the spleen of large yellow croaker Pseudosciaena crocea (LycIFITM1). The complete cDNA of LycIFITM1 is 734 nucleotides (nt) encoding a protein of 124 amino acids (aa), with a putative molecular weight of 13.6 kDa. The deduced LycIFITM1 protein is significantly homologous to interferon-inducible transmembrane proteins (IFITMs) in mammals and fish, and has the typical structural features of IFITMs, including two transmembrane domains (residues 43-63 and 90-112, respectively) and one intracellular domain between them (residues 64-89), as well as one conserved protein kinase C (PKC) phosphorylation site (residues 65-67, SIK). Phylogenetic analysis showed that LycIFITM1 formed a cluster with fish IFITM, reflecting a relative distant evolutionary relationship from mammals. LycIFITM1 gene was constitutively expressed in various tissues examined, such as gills, intestine, liver, kidney, heart, spleen, muscle and blood. Upon induction with poly(I:C), LycIFITM1 gene expression was obviously up-regulated in gills, kidney, heart and spleen at 24h after stimulation, suggesting that LycIFITM1 may be involved in the immune response induced by poly(I:C). Time course analysis using real-time PCR showed that the mRNA levels of LycIFITM1 in spleen and kidney were quickly up-regulated by poly(I:C) and reached the peak at 24h post-induction (48.7- and 280.4-fold mRNA increases in spleen and kidney, respectively). The results suggest that the IFITM1 homologue from large yellow croaker may represent a novel member of IFITMs family in fish.
在人类细胞中，干扰素诱导跨膜蛋白1（IFITM1）是参与同型黏附及抗增殖信号转导的蛋白复合物的一个组成部分。在此，我们报道了从大黄鱼（Pseudosciaena crocea）脾脏中克隆出IFITM1同源物（LycIFITM1）。LycIFITM1的完整cDNA为734个核苷酸（nt），编码一个由124个氨基酸（aa）组成的蛋白质，推测分子量为13.6 kDa。推导的LycIFITM1蛋白与哺乳动物和鱼类中的干扰素诱导跨膜蛋白（IFITMs）具有显著同源性，并且具有IFITMs的典型结构特征，包括两个跨膜结构域（分别为第43 - 63位和90 - 112位氨基酸残基）以及它们之间的一个胞内结构域（第64 - 89位氨基酸残基），还有一个保守的蛋白激酶C（PKC）磷酸化位点（第65 - 67位氨基酸残基，SIK）。系统发育分析表明，LycIFITM1与鱼类IFITM形成一个聚类，反映出其与哺乳动物相对较远的进化关系。LycIFITM1基因在检测的各种组织如鳃、肠、肝、肾、心脏、脾脏、肌肉和血液中组成性表达。用聚肌胞苷酸（poly(I:C)）诱导后，在刺激后24小时，LycIFITM1基因在鳃、肾、心脏和脾脏中的表达明显上调，表明LycIFITM1可能参与了由poly(I:C)诱导的免疫反应。使用实时PCR进行的时间进程分析表明，脾脏和肾脏中LycIFITM1的mRNA水平被poly(I:C)快速上调，并在诱导后24小时达到峰值（脾脏和肾脏中mRNA分别增加48.7倍和280.4倍）。结果表明，大黄鱼的IFITM1同源物可能代表鱼类IFITMs家族的一个新成员。
