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tRNA processing and nuclear-cytoplasmic dynamics

tRNA 加工和核质动力学

基本信息

批准号：
9920190
负责人：
Anita K Hopper
金额：
$ 32.76万
依托单位：
OHIO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-05-01 至 2021-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9920190
关键词：
Actins Address Anabolism Apoptosis Area Back Biochemical Biogenesis Biological Biological Process Biology Cell Nucleus Cells Complex Cytoplasm Cytoplasmic Protein Cytoskeleton Data Defect Disease Event Exportins Gene Expression Gene Mutation Genes Genetic Genetic Transcription Genetic study Genome Genomics Health Human Learning Malignant Neoplasms Mediating Messenger RNA Metabolic Diseases Methodology Mitochondria Mitochondrial Membrane Protein Modeling Movement Mutation Myosin Type V Neuromuscular Diseases Nuclear Nuclear Export Nuclear Import Nuclear Protein Nutrient Organelles Organism Outer Mitochondrial Membrane Pathway interactions Premature Birth Process Protein Biosynthesis Proteins Proteome Quality Control RNA RNA Processing RNA Splicing Regulation Research Research Project Summaries Reverse Transcription Role Saccharomycetales Signal Transduction Site Stress Surface Testing Transfer RNA Yeast Model System Yeasts endonuclease experimental study gene product genome wide screen in vivo mitochondrial membrane novel nuclease piRNA prevent programs protein degradation repaired response tRNA Precursor tool trafficking

项目摘要

Project Summary This research program focuses on tRNA biosynthesis and its subcellular trafficking. In addition to their essential role in protein synthesis, tRNAs are required for nutrient signaling, regulation of apoptosis, protein degradation, and priming retroviral reverse transcription. tRNA biogenesis requires a complex set of conserved gene products for post-transcriptional processing and subcellular traffic. Although for decades it was thought that tRNA movement is unidirectional, nucleus to cytoplasm, we co-discovered that tRNAs move bi- directionally between the nucleus and the cytoplasm and that the dynamics are conserved between yeast and vertebrate cells. tRNA dynamics consist of 3 steps: “primary export” of tRNA from the nucleus to the cytoplasm, “retrograde nuclear import” of cytoplasmic tRNA into the nucleus, and “re-export” of the imported tRNAs back to the cytoplasm. The mechanisms by which tRNAs move between the nucleus and the cytoplasm are not completely understood. Because tRNA nuclear export is essential and the known exporters are unessential, we conducted an unbiased genome-wide screen in yeast to search for the missing tRNA nuclear exporter(s). We discovered that mutations of two pathways utilized for protein (Crm1) and mRNA (Mex67-Mtr2) nuclear export also cause defective tRNA nuclear export; the data support the model that Crm1 and Mex67- Mtr2 function in tRNA nuclear export. Aim 1 employs in vivo biochemical analyses to test the hypothesis that tRNAs directly interact with the Crm1 and/or Mex67-Mtr2 nuclear export machinery and to learn how these alternative nuclear export pathways recognize tRNA substrates. Aim 1 also seeks to test whether a candidate tRNA nuclear importer physically interacts with tRNA. Aim 2 addresses the biological function for tRNA bi- directional traffic between the nucleus and cytoplasm. We discovered that one function is for tRNA quality control that prevents aberrant tRNA from interacting with the protein synthesis machinery. Aberrant tRNAs reach the cytoplasm, in part, due to error-prone nuclear export. We will analyze the fidelity of the parallel tRNA nuclear export pathways and determine whether aberrant tRNAs are corrected and/or destroyed upon retrograde import into the nucleus. Aim 3 addresses RNA processing steps that occur on the mitochondrial membrane. Pre-tRNA splicing in yeast and piRNA processing in metazoans occur on the mitochondrial surface. We identified proteins that likely function in directing the tRNA splicing endonuclease and/or tRNAs to mitochondria and we propose to test these roles. The information gained should inform how and why the mitochondrial surface functions as a “warehouse” for RNA processing. Thus, the proposed research program impacts upon multiple facets of gene expression, quality control, and issues important to human health.

项目总结