不同于哺乳类I型IFN基因，鱼类a亚类IFN基因在转录时推测发生了选择性剪接，但没有转录剪接发生的实验证据，且转录产生的胞内干扰素与胞外干扰素的协同抗病毒机制也需要更深入研究。本项目拟在我们前期成功体外模拟银鲫IFNa1基因转录成胞外和胞内IFN（eIFNa1和iIFNa1）两个转录本的基础上，进一步研究调控序列在介导eIFNa1和iIFNa1转录中的功能及信号通路，揭示IFNa1基因在转录成两个转录本时如何被启动表达的分子机理；研究剪接位点在介导eIFNa1和iIFNa1转录产生中的作用，揭示IFNa1基因如何通过选择性剪接表达成两个转录本的分子机制；研究胞内iIFNa1可能的胞外功能，揭示鲫IFNa1基因同时转录成胞内和胞外IFN时如何发挥抗病毒作用的分子机制。本项目的研究结果将阐明银鲫IFNa1的转录剪接及抗病毒作用机理，同时也将有助于理解鱼类具有自身特点的干扰素抗病毒反应机制。

Unlike mammalian type I IFN genes, fish type I IFN genes of subgroup a of group I have the potential to express two transcripts including extracellular IFN and intracellular IFN, which is predicated just by an alternative splicing event through bioinformatic analyses, but is not concluded from substantial experimental data. In addition, little is known about the molecular mechanism underlying the cooperatively antiviral function of the intracellular and extracellular IFNs when they both are transcribed from a single fish IFN gene. Our previous studies have successfully established an in vitro system whereby gibel carp IFNa1 is believed to generate two transcripts, eIFNa1 and iIFNa1, which in vitro mimics the transcription events of IFNa1 in virally-infected gibel carp tissues. In the current project, firstly, regulatory sequences involved in gibel carp IFNa1 gene transcription will be cloned to compare the induction pathways triggered by different IFN stimuli, thus clarifying how gibel carp IFNa1 gene is initiated for transcription in response to virus infection. Secondly, the potential effects of alternative acceptor sites and alternative donor sites in mediating transcriptional generation of eIFNa1 and iIFNa1 by IFNa1 will be determined, thus revealing how gibel carp IFNa1 expresses two transcripts by alternative splicing. Finally, whether iIFNa1 also exerts antiviral function through cell membrane IFN receptors besides cytoplasmic receptors and the cooperative antiviral effects of eIFNa1 and iIFNa1 will be further determined, thus clarifying how gibel carp IFNa1 gene function when it simultaneously generates two transcripts in response to viral infection. If this project is supported, the moelcular mechanisms underlying alternative splicing and antiviral function of gibel carp IFNa1 will be revealed and importantly, these data will aid to comprehensively understand fish-own antiviral mechanisms involved in interferon antiviral response.