ISGF3 TRANSCRIPTION FACTOR FAMILY IN CYTOKINE SIGNALING

细胞因子和生长因子的信号转导机制 受体对于理解这些受体的生理作用很重要。 细胞生长、分化和反应的重要调节因子 病原体。我们一直在定义信号转导的生物化学 用于干扰素(IFN)，并扩展了在 系统对表皮和血小板衍生生长因子(EGF和PDGF)的调节作用。 拟议的研究将定义、克隆和表征小说 受这些细胞因子调节的转录因子；决定 细胞表面受体偶联的生化机制 激活转录；识别和分离被激活的靶基因 通过细胞因子通过这一途径发挥作用；并创造突变细胞 在该信号通路中特异缺陷的品系和小鼠品系 通过同源重组进行基因打靶。了解 生长因子和细胞因子信号转导的生化机制及其研究进展 靶基因将允许定义在病理上放松调控的步骤 生长因子活性过高或不足的州，如癌症 生长抑制因子的活性导致细胞异常生长。 建立具有特定病变的突变细胞系和动物 细胞因子途径将定义细胞因子的生理后果 在正常和非正常条件下运行，并将提供新的 疾病的模型。 ISGF3转录因子家族的新成员将被克隆和 分析结构-功能关系，分析它们形成的能力 具有新的DNA结合特异性的多聚体，因为它们能够 被不同的细胞因子激活，对于它们的不同，组织- 特定的表达方式。信号偶联的生物化学 允许细胞因子和生长因子受体激活转录 因子将通过确定受体之间的联系来定义， JAK家族的激酶和转录因子底物。结构- 对EGF和PDGF受体以及JAK1激酶的功能研究将定义 连接这些蛋白质的物理相互作用和配体的机制- 诱导激活。同样，对猪细小病毒p91和p93蛋白的研究 ISGF3将定义它们如何被生长因子具体识别 和/或干扰素受体。由生长因子激活的靶基因将是 随机扩增的细胞RNA的PCR指纹图谱鉴定 在不同条件下处理。来自通配类型和的表达式模式 突变的EGF和PDGF受体将定义通过ISGF3调控的基因 路径。ISGF3p9l基因突变引起的胚胎干细胞改变 同源重组基因将被用来创造纯合子突变 动物。纯合子零细胞将被分析其能力 体外分化和在体内定植特定组织的能力 嵌合体小鼠，特别注意造血。

The mechanisms of signal transduction from cytokine and growth factor receptors are important for understanding the physiological roles of these important mediators of cell growth, differentiation, and response to pathogens. We have been defining the biochemistry of signal transduction for interferons (IFNs) and have extended the paradigm discovered in this system to the epidermal and platelet-derived growth factors (EGF & PDGF). The proposed research will define, clone and characterize novel transcription factors regulated by these cytokines; determine the biochemical mechanisms involved in coupling cell surface receptors to activation of transcription; identify and isolate target genes activated by cytokines functioning through this pathway; and create mutant cell lines and mouse strains specifically deficient in this signaling pathway by gene targeting through homologous recombination. Understanding the biochemical mechanisms of growth factor and cytokine signaling and their target genes will allow definition of steps deregulated in pathological states such as cancer where over activity of growth factors or under activity of growth inhibitory cytokines leads to abnormal cell growth. Creation of mutant cell lines and animals with specific lesions in cytokine pathways will define the physiological consequences of cytokine functioning under normal and abnormal conditions and will provide new models for disease. New members of the ISGF3 transcription factor family will be cloned and analyzed for structure-function relationships, for their ability to form multimers with novel DNA-binding specificity, for their ability to be activated by different cytokines, and for their differential, tissue- specific patterns of expression. The biochemistry of signal coupling allowing cytokine and growth factor receptors to activate transcription factors will be defined by determining the linkage between receptors, the Jak family kinases, and the transcription factor substrates. Structure- function studies of the EGF and PDGF receptor and Jak1 kinase will define physical interactions linking these proteins and the mechanisms of ligand- induced activation. Similarly, studies of the p9l and p93 proteins of ISGF3 will define how they are specifically recognized by growth factor and/or IFN receptors. Target genes activated by growth factors will be identified by arbitrarily-primed PCR fingerprinting of RNA from cells treated under different conditions. Expression patterns from wildtype and mutant EGF and PDGF receptors will define genes regulated via the ISGF3 pathway. Altered embryonic stem cells with disruption of the ISGF3 p9l gene by homologous recombination will be used to create homozygous mutant animals. Homozygous null cells will be analyzed for their capacity to differentiate in vitro and for ability to colonize specific tissues in chimeric mice, with particular attention to hematopoiesis.