Background: Currently, the pathological biochemistry of Amyotrophic Lateral Sclerosis (ALS) is poorly understood resulting in limited treatment options. Emerging research has implicated aberrant stress granules in ALS pathology (1). Stress granules are accumulations of non-membrane bound RNA-protein assemblies which aggregate in the cytosol of cells as a natural response to external stimuli (2). These stress granule assemblies are a dynamic biological response to cellular stress, limiting mRNA translation initiation to help the cell survive short-term stresses such as thermal, metabolic, and oxidative stress (3). Chronic stress granules form when the cell does not disperse the RNA-protein assemblies leading to cell death (4). Objective: To create models to study stress granule formation and disassembly in ALS in real time, in vivo. Methods: Zebrafish are the most suitable model organism for this study. Their high reproduction rate, a well characterised gene altering ‘toolkit’, and transparency in their embryonic and larval stages allow for a high number of samples to be genetically altered and screened over short time frames. Zebrafish share up to 70% of exons and major organs of interest with humans which should enable sound comparison at the cellular level of stress granule dynamics (5). In order to study stress granule formation, this project aims to link known stress granule associated proteins with fluorescent markers to visualise stress granule dynamics, in real time, in vivo, through confocal microscopy. Results/Discussion: We have injected stress granule reporters and visualised the formation of stress granules with some evidence to suggest they co-localised with ALS associated proteins. The goal for this research is to establish a model to understand stress granule dynamics and their role in ALS potentially aiding foundational steps toward better treatments or a cure. References: 1. Bosco DA, Lemay N, Ko HK, Zhou H, Burke C, Kwiatkowski TJ, Jr, et al. Mutant FUS proteins that cause amyotrophic lateral sclerosis incorporate into stress granules. Human Molecular Genetics. 2010;19(21):4160-75. 2. Kedersha N, Ivanov P, Anderson P. Stress granules and cell signaling: more than just a passing phase? Trends in Biochemical Sciences. 2013;38(10):494-506. 3. Guzikowski AR, Chen YS, Zid BM. Stress-induced mRNP granules: Form and function of processing bodies and stress granules. WIREs RNA. 2019;10(3):e1524. 4. Wolozin B, Ivanov P. Stress granules and neurodegeneration. Nature Reviews Neuroscience. 2019;20(11):649-66. 5. Howe K, Clark MD, Torroja CF, Torrance J, Berthelot C, Muffato M, et al. The zebrafish reference genome sequence and its relationship to the human genome. Nature. 2013;496(7446):498-503.