RNA Polymerase II Elongation Complex:Structure-Function

RNA 聚合酶 II 延伸复合物：结构-功能

基本信息

批准号：
7907163
负责人：
Daniel Reines
金额：
$ 8.23万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-09-18 至 2010-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7907163
关键词：
Address Binding Biochemical Biochemistry Biology Cells Chromatin Clinical Complex DNA DNA Sequence DNA-Directed RNA Polymerase Dependence Drug Delivery Systems Drug resistance Drug-sensitive Elements Elongation Factor Enzymes Etiology Eukaryota Event Evolution Failure Family Gene Dosage Gene Family Genes Genetic Genetic Transcription Genetic screening method Goals Graft Rejection Growth Guanine Guanine Nucleotides Guanosine Triphosphate Human IMP Dehydrogenase Immune response Immunosuppression Immunosuppressive Agents In Vitro Indium Individual Investigation Kidney Transplantation Learning Length Life Link Measures Mediating Messenger RNA Molecular Genetics Mutation Mycophenolate Mycophenolic Acid Nucleotides Organism Pathway interactions Patients Persons Pharmaceutical Preparations Phenotype Process Property Protein Isoforms Proteins RNA RNA Polymerase II RNA Splicing Regulation Research Personnel Resistance Response Elements Retinitis Pigmentosa Saccharomyces cerevisiae Sampling Structure T-Cell Proliferation T-Lymphocyte Testing Time Transcript Transcription Initiation Site Transplant Recipients Treatment Efficacy Yeasts azauracil cell growth drug sensitivity in vivo inhibitor/antagonist lymphocyte proliferation mutant novel nucleotide metabolism prevent programs promoter response transcription factor S-II yeast genetics

项目摘要

DESCRIPTION (provided by applicant): The elongation of transcripts by RNA polymerase II is a complex process dependent upon nucleotide substrate levels, elongation factors, and co-transcriptional events such as splicing. Mutations in genes encoding elongation factor SI I (TFIIS), other elongation factors, RNA polymerase subunits, and chromatin related proteins, render S. cerevisiae sensitive to the drugs 6-azauracil and mycophenolic acid. These drugs are inhibitors of IMP dehydrogenase (IMPDH) which is a critical enzyme in the de novo pathway of guanine nucleotide synthesis. Its abundance is positively correlated with cell growth in eukaryotes from yeast to humans. Drug treated yeast respond by transcriptional induction of one of their four IMPDH genes. The response is reliant upon an optimally functioning elongation machinery. In humans, T lymphocyte proliferation during an immune response is highly dependent upon IMPDH synthesis. Mycophenolic acid inhibits T cell proliferation and is an important clinical immunosuppressant that inhibits graft rejection in kidney transplant (and other) patients. Mutations in IMPDH have also been implicated in the etiology of retinitis pigmentosa. Regulation of the essential yeast IMPDH gene family is mediated through a cellular mechanism that senses nucleotide pools. This project will use biochemistry and genetics to understand this regulation of IMPDH transcription through novel DNA elements. One sequence is a potent repressive element which encompasses the transcription start site and may regulate elongation. Yeast contain a complex family of IMPDH isoforms with varying sensitivity to mycophenolic acid inhibition. The potential of IMPDH to form heteromeric complexes between drug resistant and sensitive subunits will be addressed. The drug sensitive phenotype of yeast lacking their IMPDH genes will be useful in studying resistant and sensitive forms in humans. Resistance to IMPDH-directed drugs is an important clinical issue given the wide spread and lifelong treatment of transplant patients with mycophenolate. The ability of normal T cells, and T cells from patients receiving therapy, to respond to the drug by altering IMPDH expression and activity, will be examined. Differences between the responses of different individuals will be quantified. This will be important for the long term goal of understanding potential genetic differences in the efficacy of therapy and responsiveness of patients to immunosuppressants that target IMPDH.

描述（由申请人提供）： RNA聚合酶II对转录本的延伸是一个复杂的过程，取决于核苷酸底物水平、延伸因子和剪接等共转录事件。编码延伸因子 SI I (TFIIS)、其他延伸因子、RNA 聚合酶亚基和染色质相关蛋白的基因突变，使得酿酒酵母对药物 6-氮尿嘧啶和霉酚酸敏感。这些药物是 IMP 脱氢酶 (IMPDH) 的抑制剂，IMPDH 是鸟嘌呤核苷酸从头合成途径中的关键酶。它的丰度与从酵母到人类的真核生物的细胞生长呈正相关。药物处理的酵母通过其四个 IMPDH 基因之一的转录诱导来做出反应。该响应依赖于最佳运行的伸长机制。在人类中，免疫反应过程中 T 淋巴细胞的增殖高度依赖于 IMPDH 的合成。霉酚酸可抑制 T 细胞增殖，是一种重要的临床免疫抑制剂，可抑制肾移植（和其他）患者的移植物排斥反应。 IMPDH 突变也与色素性视网膜炎的病因有关。酵母必需 IMPDH 基因家族的调节是通过感知核苷酸池的细胞机制介导的。该项目将利用生物化学和遗传学来了解 IMPDH 转录通过新型 DNA 元件的调节。一个序列是一种有效的抑制元件，它包含转录起始位点并可以调节延伸。酵母含有复杂的 IMPDH 亚型家族，对霉酚酸抑制的敏感性不同。将讨论 IMPDH 在耐药亚基和敏感亚基之间形成异聚复合物的潜力。缺乏 IMPDH 基因的酵母的药物敏感表型将有助于研究人类的耐药和敏感形式。鉴于霉酚酸酯对移植患者的广泛普及和终身治疗，对 IMPDH 导向药物的耐药性是一个重要的临床问题。将检查正常 T 细胞和接受治疗的患者的 T 细胞通过改变 IMPDH 表达和活性对药物做出反应的能力。不同个体的反应之间的差异将被量化。这对于了解治疗效果和患者对针对 IMPDH 的免疫抑制剂的反应性方面的潜在遗传差异的长期目标非常重要。