Gene Regulation In The Immune System

免疫系统中的基因调控

• 批准号: 6671869
• 负责人: Keiko Ozato
• 金额: --
• 依托单位: EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6671869
• 关键词: 3T3 cells; cell growth regulation; chronic myelogenous leukemia; genetic regulation; genetic regulatory element; genetic transcription; immune system; immunogenetics; interferon gamma; laboratory mouse; lipopolysaccharides; neoplasm /cancer immunology; polymerase chain reaction; protein structure function; tissue /cell culture; transcription factor; transfection; tumor suppressor proteins

This section is interested in transcription factors that regulate the development of the immune system. We previously isolated ICSBP/IRF-8, a DNA specific transcription factor expressed in hematopoietic cells and showed that it regulates the development of bone marrow progenitor cells to generate macrophages and granulocytes. We also showed that introduction of ICSBP rescues normal growth and differentiation of these cells in ICSBP-null progenitors. It can also rescue the development and maturation of dendritic cells (DCs), cells important for host defense, which are profoundly defective in ICSBP-null mice. We found that a critical target gene controlled by ICSBP is IL-12p40, a cytokine expressed in macrophages and DCs and is critical for establishing innate immunity. Although IL-12p40 is not produced in ICSBP-/- macrophages and DCs, reintroduction of ICSBP can fully restore the cytokine production. By DNA microarray analysis with 15,000 murine cDNAs, we have begun to identify additional target genes that are directly regulated by ICSBP. About 50 known and unknown genes are found to be either increased or decreased following ICSBP expression, some of which are known to be important for macrophage/DC function. Studies of target promoters and the chromatin status of ICSBP-null cells suggest that this factor regulates gene expression not only by controlling target promoters, but regulating the activity of chromatin. We study the role of chromatin from another perspective, and characterize a bromodomain protein Brd4. Brd4 is a novel member of the conserved BET family, that contains a motif indicative of interaction with chromatin. We showed that it associates with mitotic chromosomes, consistent with a strong affinity for chromatin. Recent FRET and FLIP analyses suggest that Brd4 and a related protein interact with acetylated histones in living cells. By an over-expression strategy, Brd4 is found to regulate cell growth. We show that this growth regulation is partly attributed to the interaction of Brd4 with RFC, conserved DNA replication machinery, which occurs through the bromodomain. Further elucidation of the role of this factor is pursued by conditional knock-out and antisense/RNAi approaches.

本节对调节免疫系统发展的转录因子感兴趣。我们先前分离了ICSBP/IRF-8，这是一种在造血细胞中表达的DNA特异性转录因子，并表明它调节骨髓祖细胞的发育以产生巨噬细胞和颗粒细胞。我们还表明，ICSBP的引入可以挽救ICSBP无效祖细胞中这些细胞的正常生长和分化。它还可以挽救树突状细胞（DC）的发育和成熟，对宿主防御很重要的细胞，这些细胞在ICSBP无效的小鼠中非常有缺陷。我们发现，由ICSBP控制的关键靶基因是IL-12P40，这是一种在巨噬细胞和DC中表达的细胞因子，对于建立先天免疫力至关重要。尽管IL-12P40并未在ICSBP - / - 巨噬细胞和DC中产生，但重新引入ICSBP可以完全恢复细胞因子的产生。通过使用15,000个鼠cDNA的DNA微阵列分析，我们开始鉴定由ICSBP直接调节的其他靶基因。发现ICSBP表达后，大约有50个已知和未知基因增加或减少，其中一些对于巨噬细胞/DC功能很重要。对靶启动子和ICSBP无效细胞的染色质状态的研究表明，该因子不仅通过控制靶启动子来调节基因表达，而且调节染色质的活性。 我们从另一个角度研究染色质的作用，并表征了溴结构域蛋白BRD4的作用。 BRD4是保守BET家族的新成员，其中包含指示与染色质相互作用的基序。我们表明它与有丝分裂染色体相关，与染色质的强亲和力一致。最近的FRET和FLIP分析表明，BRD4和相关蛋白与活细胞中的乙酰化组蛋白相互作用。通过过表达的策略，发现BRD4可以调节细胞生长。我们表明，这种生长调节部分归因于BRD4与RFC，保守的DNA复制机制的相互作用，该复制机制通过溴化域发生。有条件的敲除和反义/RNAi方法可以进一步阐明该因素的作用。