Zhang Yi-bing, Hu Cheng-yu, Zhang Jing, Huang Guo-ping, Wei Li-hua, Zhang Qi-ya, Gui Jian-fang
State Key Laboratory of Freshwater Ecology and Biotechnology, Wuhan Center for Developmental Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
Fish Shellfish Immunol. 2003 Nov;15(5):453-66. doi: 10.1016/s1050-4648(03)00025-1.
Interferon (IFN) can induce an antiviral state via interferon-regulatory transcription factors (IRFs), which bind to and control genes directed by the interferon-stimulated response element (ISRE). Here we describe a fish IRF, termed CaIRF7, cloned from a subtractive cDNA library which is constructed with mRNAs obtained from crucian carp (Carassius auratus L.) blastulae embryonic (CAB) cells infected by UV-inactivated GCHV and mock-infected cells. CaIRF7 cDNA was found to be 1816 bp in length, with a 42 bp 5'UTR and a 508 bp 3'UTR. The open reading frame translates into 421 amino acids in which a DNA-binding domain (DBD) containing the repeated tryptophan motif and IRFs association domain have been identified. Like chicken GgIRF3, CaIRF7 was most similar to mammalian IRF7 with 27 to 30% identity overall and some 37% identity in their DBDs. A single transcript of 1.9 kb was detected in virally induced CAB cells by virtual Northern blotting. RT-PCR analysis revealed a wide tissue distribution of CaIRF7 constitutive expression, with detectable transcript in non-infected CAB cells and various tissues of healthy crucian carp. In addition, CaIRF7 expression was differentially increased by stimulation of the CAB cells with active GCHV, UV-inactivated GCHV or CAB IFN, indicating that the activation of CaIRF7 was directly regulated by IFN.
干扰素（IFN）可通过干扰素调节转录因子（IRF）诱导抗病毒状态，这些转录因子与干扰素刺激反应元件（ISRE）所指导的基因结合并对其进行调控。在此，我们描述了一种鱼类IRF，命名为CaIRF7，它是从一个消减cDNA文库中克隆得到的，该文库是用从经紫外线灭活的草鱼呼肠孤病毒（GCHV）感染的鲫鱼（Carassius auratus L.）囊胚胚胎（CAB）细胞和模拟感染细胞中获得的mRNA构建而成的。发现CaIRF7 cDNA长度为1816 bp，具有42 bp的5'非翻译区（UTR）和508 bp的3'UTR。开放阅读框编码421个氨基酸，其中已鉴定出含有重复色氨酸基序的DNA结合结构域（DBD）和IRF关联结构域。与鸡的GgIRF3一样，CaIRF7与哺乳动物的IRF7最为相似，总体一致性为27%至30%，其DBD的一致性约为37%。通过虚拟Northern印迹法在病毒诱导的CAB细胞中检测到一条1.9 kb的单一转录本。RT-PCR分析显示CaIRF7组成型表达在组织中分布广泛，在未感染的CAB细胞和健康鲫鱼的各种组织中均可检测到转录本。此外，用活性GCHV、紫外线灭活的GCHV或CAB IFN刺激CAB细胞后，CaIRF7的表达差异增加，表明CaIRF7的激活直接受IFN调控。
