NSF Award
0920229
This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).<br/><br/>This research project addresses the intricate interplay between global and messenger RNA-specific control of protein synthesis. The overall problem is exemplified by the environmental stress response pathway. When cells experience stress, they shut down their biosynthetic activity and mount an integrated response. Global protein translation ceases, in order to prevent the accumulation of misfolded proteins and to conserve amino acids and energy required for recovery. Against this backdrop of translational repression, however, certain proteins must be made for recovery to occur. These considerations illustrate the need for mRNA-specific translation control mechanisms that tightly interlock with global control.<br/><br/>This project focuses on the fission yeast eIF3e protein, a component of the multisubunit eukaryotic initiation factor 3 complex (eIF3). Cells deleted for eif3e have several cellular alterations. Firstly, under routine culture conditions, the mutant displays defects in cell morphology and growth, suggesting that eIF3e regulates the synthesis of proteins involved in these processes. However, these functions are not essential for cell viability. Secondly, eif3e mutants display broad stress sensitivity. This includes sensitivity to nutrient starvation, osmotic, oxidative, and thermal stress. Therefore, eIF3e has essential functions in the stress response. <br/><br/>The biochemical basis of the essential and non-essential functions of eIF3e in stressed vs. unstressed cells is not known. This research addresses the hypothesis that lack of eIF3e leads to the observed defects because protein synthesis is impaired at either at a global or mRNA-specific level. The goal is to distinguish between these two models and to identify the essential and non-essential target mRNAs of eIF3e. Unbiased global transcriptomic and proteomic profiling will be employed to identify those mRNAs that require eIF3e for their translation into protein in unstressed and stressed cells and to determine at what stage during protein synthesis eIF3e is required.<br/><br/>Broader Impacts. This research will generate several unique large scale datasets that will be publicly available. These include quantitative data on global protein expression and translational competence in stressed and unstressed fission yeast cells. Due to the high degree of conservation of basic cellular pathways in fission yeast, these data will also be relevant to other biological systems, including plants and mammals. This research will also create a variety of training opportunities for students at several levels. As part of the research effort, graduate and undergraduate students will become familiar with modern high-throughput technologies such as DNA microarrays and peptide tandem mass spectrometry. Quarterly training sessions will be offered to familiarize technicians, graduate students, and postdoctoral associates with quantitative proteomics techniques. Finally, the project will be integrated into an ongoing partnership with the California State University, Fresno, which is a primarily Hispanic-serving institution. Within the framework of this liaison, minority undergraduate students from Fresno State will be visiting the Burnham Institute for 10-week lab rotations over the summer to work on this project.
