The Function of rpL5 and rpL11 in induction of p53

rpL5和rpL11在p53诱导中的作用

基本信息

批准号：
8434834
负责人：
GEORGE THOMAS
金额：
$ 30.62万
依托单位：
UNIVERSITY OF CINCINNATI
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-03-01 至 2017-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8434834
关键词：
Abnormal Cell Acute Myelocytic Leukemia Antigens Binding Biochemical Biogenesis Biological Models Cell Cycle Arrest Cell Cycle Progression Cell Line Cell Proliferation Cell division Cells Cellular Structures Complement Complex DNA Polymerase III Dactinomycin Data Defect Development Diamond-Blackfan anemia Disease Double Minutes Drosophila genus Dysmyelopoietic Syndromes Genes Genetic Programming Genetic Translation Growth Human Human Pathology Impairment Laboratory Study Lesion Life Lymphoma MDM2 gene Malignant Neoplasms Mediating Messenger RNA Mitotic Cell Cycle Modeling Molecular Monitor Mutation Normal Cell Patients Pattern Polymerase Process Production Proliferating Protein Biosynthesis Proteins RNA, Ribosomal, 5S Ribosomal Proteins Ribosomal RNA Ribosomes Role Site Sjogren&apos s Syndrome Syndrome Testing Transcription Factor TFIIIA Translations Tumor Biology Tumor Suppressor Proteins Up-Regulation Work Zebrafish cancer cell cancer therapy cell growth chromosome 5q loss daughter cell design human FRAP1 protein neoplastic cell novel prevent response tool tumor tumor progression tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): A proliferating cell expends most of its energy in the biogenesis of nascent ribosomes. The increased number of ribosomes provides the translational capacity required for the cell to synthesize the full complement of proteins necessary to enter the mitotic cell cycle and divide. The importance of ribosome biogenesis to cell proliferation is underscored by the fact that a lesion in ribosome biogenesis alters the ratio of ribosomes to mRNA, which eventually modifies the pattern of translation and the genetic program, resulting in aberrant growth. Given these observations, we initially predicted that cells would have evolved a checkpoint to monitor nascent ribosome biogenesis. The importance of this concept to human pathology has been demonstrated in two haemopoietic disorders, 5q- syndrome and Diamond Blackfan Anemia (DBA), which are characterized by hypomorphic mutations or deletions in ribosomal protein (rp) genes. Patients with these diseases first develop myelodysplasias, but have the propensity to progress to a wide range of cancers later in life, particularly acute myeloid leukemia (AML). The concept that rp genes act as haploinsufficient tumor suppressors initially came from studies in model systems, including Drosophila and zebrafish. Recent studies from this laboratory have provided a model to explain both the myelodysplasia and the potential to develop cancer. We showed that upon disruption of either 40S or 60S ribosome biogenesis there is an upregulation of p53 mediated by the binding of the 60S rps, rpL5 and rpL11, to human double minute 2 (MDM2 or Hdm2), leads to G1 cell-cycle arrest. However, in circumstances where 40S, but not 60S, ribosome biogenesis is impaired, this effect requires the translational upregulation of rpL5 and rpL11 to generate sufficient protein to bind to Hdm2 in the face of continued 60S ribosome biogenesis and a decrease in global protein synthesis. The translational upregulation of rpL5 and rpL11 is dependent on the 5' TOP sequence, which acts as translational repressor, and resides at the transcriptional start site of rp mRNAs. Loss of this checkpoint is most likely responsible for the propensity of 5q- syndrome and DBA patients to develop AML. The importance of this checkpoint in p53 positive tumors is underscored by two findings: (i) the extent of tumor progression directly parallels nucleolar size and RNA polymerase 1 (Pol 1) activity and (ii) actinomycin D, which at low concentrations, selectively inhibits RNA Pol 1, arrests p53/MDM2 wild type (WT) tumor cells in G1. Together, these observations have led us to hypothesize that the rpL5/rpL11 complex is upregulated in response to impaired ribosome biogenesis to induce p53 cell-cycle arrest and to prevent tumor progression. These studies are relevant to tumor biology as they are designed to elucidate the mechanism by which impaired ribosome biogenesis mediates cell cycle progression, the identification of components in addition to rp5/rpL11 which mediate this response, and the role of general translation versus the p53 checkpoint in controlling tumor progression beyond 5q- syndrome and DBA, which will aid in the development of novel cancer treatments.

描述（由申请人提供）：增殖细胞在新生核糖体的生物发生中消耗大部分能量。核糖体数量的增加提供了整个细胞所需的翻译能力，以综合进入有丝分裂细胞周期和分裂所需的蛋白质的完整补体。核糖体生物发生与细胞增殖的重要性是由于核糖体生物发生的病变改变了核糖体与mRNA的比例，最终改变了翻译和遗传程序的模式，从而导致异常生长。鉴于这些观察结果，我们最初预测细胞会进化一个检查点以监测新生的核糖体生物发生。这一概念对人类病理的重要性已在两种造血性疾病（5q-综合征和钻石黑芬贫血（DBA））中得到证明，这些疾病的特征是核糖体蛋白（RP）基因中的肌密封突变或缺失。这些疾病的患者首先发展出骨髓增生性，但倾向于在生活后期的癌症中发展到广泛的癌症，尤其是急性髓性白血病（AML）。 RP基因作为单倍抑制肿瘤抑制剂的概念最初来自包括果蝇和斑马鱼在内的模型系统中的研究。该实验室的最新研究提供了一个模型来解释骨髓增生和发展癌症的潜力。我们表明，在破坏40s或60s核糖体生物发生后，由60S RPS，RPL5和RPL11的结合与人双分钟2（MDM2或HDM2）（MDM2或HDM2）介导的p53上调，导致G1细胞周期停滞。但是，在40s而不是60s的情况下，核糖体生物发生受损，这种效应需要RPL5和RPL11的翻译上调，以产生足够的蛋白质，面对持续的60S核糖体生物发生，并减少全球蛋白质合成。 RPL5和RPL11的翻译上调取决于5'顶级序列，该序列充当翻译阻遏物，并且位于RP mRNA的转录起始位点。该检查点的丢失很可能导致5Q-综合征和DBA患者发展AML的倾向。该检查点在p53阳性肿瘤中的重要性被两个发现强调：（i）肿瘤进展的程度直接与核仁的大小和RNA聚合酶1（POL 1）活性和（ii）肌动蛋白D相平均，在低浓度下，在低浓度下，选择性地抑制RNA POL 1，抑制P53/MDM2 Wild type（w t tumor tamor tymor tamor tumor cy g1）总之，这些观察结果导致我们假设RPL5/RPL11复合物响应受损的核糖体生物发生，以诱导p53细胞周期停滞并防止肿瘤进展。这些研究与肿瘤生物学有关，因为它们旨在阐明核糖体生物发生受损的机制，核糖体生物发生介导了细胞周期的进展，除RP5/RPL11外，还鉴定了介导这种反应的组件以及一般翻译的作用以及p53检查点在控制肿瘤进展中的p53检查点的作用超过5q-综合症和DBA，这将有助于5q-综合症和DBA的发展。