In a genetic screen conducted in adult zebrafish to select mutations that disrupt age-related neuronal homeostasis, 36 genes were identified. Many of these loci have previously been shown as associated or causative to human neurodegenerations such as Alzheimer's, Huntington's, Parkinson's and Spinocerebellar Ataxia diseases. This proposal describes experiments to address cellular functions of a subset of the genes identified from this screen with unknown mechanisms of action. First, complete loss of function mutations will be generated in this subset though engineered large genomic deletions within coding sequence. Next, these will be analyzed for their impact on neuronal homeostasis by monitoring several cellular stress responsive pathways known to be activated during neurodegeneration including the ER stress/Unfolded Protein Response, Oxidative Stress Response, and Autophagy/Mitophagy. In anticipation of these studies, our group has established imaging-based reporters for each of these processes. In addition, mutants will also be evaluated in the context of several sensitized genetic strains in which these stress-responsive pathways have been compromised. Finally, the autonomy of mutant impact will be investigated through cell-type specific gene disruption in multiple neuronal and non-neuronal cell types. These studies will provide important base-line information and rationale for carrying out next-step analysis in mammalian, including human, homologues that may represent critical targets for therapeutic intervention to promote neuronal health and prevent neurodegeneration.
This proposal describes basic science research to understand the fundamental cellular functions of factors identified in a zebrafish genetic screen for mutations that disrupt normal age-dependent neuronal homeostasis. Several of the genes identified in this screen have previously been associated with human neurodegenerations such as Alzheimer's, Huntington's, Parkinson's and Spinocerebellar Ataxia diseases; another subset of the identified genes have not been well characterized and were selected on their novelty for functional characterization. This proposal outlines strategies to assess their roles in age-dependent neuronal homeostasis in multiple neuronal, glial, and other cell types.
