Selective gene activation by the NF-kappaB family of transcription factors

转录因子 NF-kappaB 家族的选择性基因激活

• 批准号: 7755386
• 负责人: Stephen T Smale
• 金额: $ 36.68万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-01 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7755386
• 关键词: Affinity; Bacterial Artificial Chromosomes; Binding; Biological Assay; Biological Process; Bone Marrow; Cells; Chimera organism; Chimeric Proteins; Chronic; Communicable Diseases; Consensus; DNA; DNA Binding; Dependence; Dimerization; Disease; Event; Exhibits; Family; Family member; Gene Activation; Gene Targeting; Genes; Immune response; Immune system; Individual; Inflammatory; Interleukin-12; Knowledge; Lead; Learning; Mus; NF-kappa B; Pathway interactions; Phenotype; Physiological; Play; Property; Proteins; Publishing; Research Personnel; Role; Series; Signal Transduction; Specificity; Stimulus; Suggestion; TNFRSF5 gene; Testing; Time; Transactivation; Transcriptional Activation; Transfection; Transgenic Mice; Variant; base; combat; cytokine; dimer; insight; interest; macrophage; member; novel strategies; p65; programs; research study; response; success; transcription factor

DESCRIPTION (provided by applicant): Members of the NF-?B/Rel family of transcription factors are well-established as critical regulators of pro- inflammatory genes in cells of the innate immune system, and they play important roles in several other biological processes. The phenotypes of mice lacking individual NF-?B family members suggest that each protein targets unique sets of genes. However, although much has been learned about the signal transduction mechanisms that activate NF-?B dimers in response to various stimuli, the fundamental reasons different NF-?B dimers are capable of regulating different genes remain largely unexplored. Because some genes that require a specific NF-?B family member for expression play critical roles in dictating the type of immune response elicited by a stimulus, an understanding of the mechanistic basis of family member selectivity may lead to novel strategies for modulating immune responses with an unusually high degree of specificity, to more effectively combat infectious diseases and chronic inflammatory diseases. We became interested in the mechanisms of NF-?B family member selectivity when we found that the II12b gene, which encodes the p40 subunit of the pro-inflammatory cytokine IL-12, exhibits an unusually strong requirement for the c-Rel member of the NF-?B family. Because earlier studies had shown that the DNA- contacting residues of c-Rel are identical to those of another family member, p65, and that the DNA recognition sequences for c-Rel and p65 are similar, we asked why c-Rel, but not p65, is critical for Il12b activation. Our results provided compelling evidence that c-Rel is required because c-Rel homodimers can bind non-consensus NF-?B sequences with high affinity, whereas p65 homodimers bind with high affinity only to sequences that closely match the NF-?B consensus. Notably, 46 residues of c-Rel were found to be responsible for its unique DNA-binding properties. To further elucidate NF-?B selectivity mechanisms, we will first use a variety of interconnected strategies to advance our knowledge of gene activation by c-Rel. We will also prepare bacterial artificial chromosome (BAC) transgenic mice to examine more rigorously the hypothesis that the 46 residues of c-Rel are fully responsible for its unique functions. Finally, because of the success of our p65-c-Rel chimeric protein strategy for uncovering c-Rel selectively mechanisms, we will use this same strategy as a starting point toward understanding the mechanism of selective gene activation by p65.

描述（由申请人提供）：转录因子的NF-？b/rel家族的成员是良好的结合者，是先天免疫系统细胞中炎症基因的关键调节剂，并且它们在其他几种生物过程中起着重要作用。缺乏单个NF-？B家族成员的小鼠的表型表明，每种蛋白质都靶向独特的基因集。但是，尽管已经了解了激活NF-二聚体的信号转导机制，以响应各种刺激，但基本原因不同的NF-二聚体能够调节不同的基因，但仍无法探索不同的基因。因为某些需要特定NF-？B家族成员来表达表达的基因在决定刺激引起的免疫反应类型中起着关键作用，因此对家庭成员选择性的机理基础的理解可能会导致新的策略，以调节具有异常高度特异性的免疫反应，从而更有效地有效地抗击感染性疾病和慢性疾病。当我们发现编码促炎性细胞因子IL-12的p40亚基时，我们对NF-？b家族成员选择性的机制感兴趣。由于较早的研究表明，C-Rel的DNA接触残基与另一家族成员P65的DNA接触残基相同，并且C-REL和P65的DNA识别序列相似，因此我们问为什么C-REL（而不是P65）对于IL12B激活至关重要。我们的结果提供了令人信服的证据，表明需要C-REL，因为C-REL同型二聚体可以结合具有高亲和力的非传感NF-？B序列，而P65同型二聚体仅与高亲和力结合，仅与与NF-？B共识紧密匹配的序列。值得注意的是，发现46个C-REL残基是其独特的DNA结合特性的原因。为了进一步阐明NF-？b选择性机制，我们将首先使用各种相互联系的策略来提高我们对C-Rel的基因激活知识。我们还将准备细菌性人造染色体（BAC）转基因小鼠，以更严格地检查C-Rel的46个残基完全负责其独特功能。最后，由于我们的p65-C-REL嵌合蛋白策略成功地揭示了C-Rel选择性机制，因此我们将使用该策略来理解p65选择性基因激活的机制的起点。