Reverse Transcriptase Activity in Megakaryocytes and Platelets

巨核细胞和血小板中的逆转录酶活性

基本信息

批准号：
7845031
负责人：
Andrew S Weyrich
金额：
$ 18.81万
依托单位：
UNIVERSITY OF UTAH
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：
2009-07-01 至 2011-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7845031
关键词：
2&apos -Deoxythymidine Abbreviations Affect B-Cell Lymphomas Blood Platelets Cell Nucleus Cells Clinical Code Complementary DNA DNA Elements Eukaryotic Cell Family Functional RNA Gene Expression Genes Genetic Transcription Genome Genomics HERVs HIV Hemophilia A Human Human Activities Individual Information Distribution Interleukin-1 Introns L1 Elements Link Long Terminal Repeats Megakaryocytes Megakaryocytopoieses Messenger RNA Mitochondrial DNA Molecular Chaperones Muscle Nuclear Nucleic Acids Open Reading Frames Pathway interactions Patients Pattern Phosphotransferases Platelet Transfusion Process Proteins RNA RNA Splicing RNA-Binding Proteins RNA-Directed DNA Polymerase Retrotransposon Reverse Transcriptase Inhibitors Reverse Transcription Role Signal Transduction Site Small Nuclear RNA Small Nuclear Ribonucleoproteins Spliceosomes Stereotyping Stimulus Structure Testing Thalassemia Thromboplastin Thrombopoiesis Time Untranslated Regions Uridine Work Zidovudine cell growth endonuclease human FRAP1 protein human stem cells insight mRNA Precursor mTOR protein non-nucleoside reverse transcriptase inhibitors novel response

项目摘要

DESCRIPTION (provided by applicant): The nucleus controls gene expression patterns that characterize the function of individual cells. Responses that occur in the nucleus, such as transcription and splicing of pre-mRNA, are elaborate processes that utilize many factors. Because platelets circulate without a nucleus, they have been stereotyped as a cell that lacks complexity and is devoid of nuclear functions. However, our group has recently shown that platelets carry a functional spliceosome and in response to activating signals, platelets splice pre- mRNA into mature, translatable messages. This result was unexpected because pre- mRNA splicing was previously thought to reside only in the nucleus. Possession of a functional spliceosome demonstrates remarkable specialization and intricate information transfer from parental megakaryocytes to terminally differentiated platelets. It also raises the possibility that megakaryocytes endow platelets with other novel gene expression pathways during thrombopoiesis. Recent evidence indicates that the long interspersed nuclear element (LINE-1; also referred to as L1 elements) family of retrotransposons harbor reverse transcriptase activity that regulates cellular growth, differentiation and gene expression. This suggests that L1 elements may regulate megakaryopoiesis and proplatelet formation. If transferred to proplatelets, L1 elements may also control functional responses in mature, circulating platelets. Whether L1 elements control megakaryocyte and platelet function, however, has not been tested. Therefore, in this R21 application we will explore the possibility that megakaryocytes and platelets possess functional L1 elements. In specific aim 1 we will characterize the L1 machinery in megakaryocytes. We will determine if L1 encoded proteins are present in human stem cell-derived megakaryocytes and if they regulate megakaryocyte differentiation and proplatelet formation. In aim 2 we will characterize the L1 machinery in mature, human platelets. We will determine if L1 elements are present in platelets and if they possess reverse transcriptase activity. We also determine if L1 elements control previously-unrecognized functions of platelets that include insertion of L1 sequences into mitochondrial DNA and reverse transcription of mRNA into cDNA. Studies in aim 2 will examine responses in freshly-isolated platelets and in stored platelets that would otherwise be used for platelet transfusions. Together these studies will provide novel insight into the cellular activities of human megakaryocytes and platelets. Studies in aim 2 will also provide important clinical information, especially in regards to HIV-infected patients who are medicated with reverse transcriptase inhibitors and patients who receive platelet transfusions.

描述（由申请人提供）：核控制着表征单个细胞功能的基因表达模式。在细胞核中发生的反应，例如前MRNA的转录和剪接，是利用许多因素的详尽过程。由于血小板在没有核的没有核的情况下循环，因此它们被定型为缺乏复杂性且缺乏核功能的细胞。但是，我们的小组最近表明，血小板具有功能性剪接体，并且在激活信号，血小板剪接前mRNA中响应成熟的，可翻译的消息。该结果是出乎意料的，因为以前认为mRNA剪接仅存在于细胞核中。拥有功能性剪接体表明，从亲本巨核细胞到终止分化的血小板的非凡专业化和复杂的信息转移。这也提高了巨核细胞在血小板中具有其他新型基因表达途径的可能性。最近的证据表明，长期散布的核元件（线1；也称为L1元素）逆转录座家族具有调节细胞生长，分化和基因表达的逆转录酶活性。这表明L1元素可以调节巨核菌和预言形成。如果转移到预言中，L1元素还可以控制成熟的循环血小板中的功能响应。但是，L1元素是否控制巨核细胞和血小板功能，尚未测试。因此，在此R21应用中，我们将探讨巨核细胞和血小板具有功能性L1元素的可能性。在特定目标1中，我们将表征巨核细胞中的L1机械。我们将确定在人类干细胞衍生的巨核细胞中是否存在L1编码的蛋白质，以及它们是否调节巨核细胞分化和预言形成。在AIM 2中，我们将以成熟的人类血小板中的L1机械进行表征。我们将确定血小板中是否存在L1元素以及它们是否具有逆转录酶活性。我们还确定L1元素是否控制了血小板的先前未认可的功能，包括将L1序列插入线粒体DNA中，并将mRNA逆转录到cDNA中。 AIM 2中的研究将检查新鲜分离的血小板和存储的血小板中的反应，否则将用于血小板输血。这些研究将共同提供对人巨核细胞和血小板的细胞活性的新见解。 AIM 2中的研究还将提供重要的临床信息，尤其是在感染了逆转录酶抑制剂和接受血小板输血的患者的HIV感染患者方面。