BETA R1 GENE: MODEL SYSTEM TO STUDY IFN BETA SIGNALING

I型干扰素包括ifn - α的10多个亚型，以及ifn - β、IFN-tau和IFN-omega。这些相关的细胞因子都通过IFN α / β受体发出信号，IFN α / β受体是由两个跨膜组分（ifnar - 1 /2）和两个非受体蛋白酪氨酸激酶TYK2和JAK1组成的复合物。最近已经很清楚，通过这种受体复合物与其各种配体的结合可以产生不同的信号。用ifn - β治疗的两个不同的结果已经被描述：被称为β - r1的基因的诱导转录，以及ifn - β与两个受体链的稳定复合物的组装。我们提出β - rl的诱导需要通过ifnar - 1 /2复合体的共同和独特信号。这一假设是基于我们的初步结果，该结果表明β - ri转录依赖于形成转录因子ISGF3所需的所有成分，但对磷酸肌醇-3激酶（PI3K）抑制剂异常敏感，并表现出对催化活性TYK2的异常需求。本研究方案提出了一个假设，即与ifn - α相比，13-RI转录依赖于通过IFNAR-1/2复合体响应ifn - β的构象依赖性信号。该信号通路通过催化TYK2和PI3K以及ISGF3起作用。具体目的是：1)表征ifn - β信号传导到β 3- rl启动子；2)产生对ifn - β选择性无反应的细胞，3)决定ifn - β选择性调节的基因表达。这些目标的实现将有助于深入了解IFN- β特异性信号传导，并有助于阐明辅助成分（如PI3K）在I型IFN反应途径中的功能作用。

Type I interferons include more than l0 subtypes of IFN-alpha, as well as IFN-beta, IFN-tau and IFN-omega. These related cytokines all signal through the IFN alpha/beta receptor, a complex composed of two transmembrane components (IFNAR-l/2) and two nonreceptor protein tyrosine kinases, TYK2 and JAK1. It has recently become clear that diverse signals can be generated by engagement of this receptor complex with its various ligands. Two distinctive outcomes of treatment with IFN-beta have been described: inducible transcription of a gene termed beta-R1, and assembly of a stable complex of IFN-beta with the two receptor chains. We propose that the induction of beta-Rl requires both common and unique signaling through the IFNAR-l/2 complex. This hypothesis is based on our preliminary results, which demonstrate that beta-RI transcription is dependent on all components needed to form the transcription factor ISGF3, but is atypically sensitive to phosphoinositol-3 kinase (PI3K) inhibitors and exhibits an unusual requirement for catalytically active TYK2. This research proposal addresses the hypothesis that 13-RI transcription depends on conformation-dependent signaling through the IFNAR-1/2 complex in response to IFN-beta as compared with IFN-alpha. This signaling pathway acts through catalytic TYK2 and PI3K, as well as ISGF3. The specific aims are to: l) characterize IFN-beta signaling to the beta3-Rl promoter; 2) generate cells selectively unresponsive to IFN-beta and 3) determine gene expression selectively regulated by IFN-beta. Performance of these aims will provide insight into IFN-beta-specific signaling and help clarify the functional roles of accessory components, such as PI3K, in type I IFN response pathway.