Project Summary/Abstract
Alternative splicing is a fundamental gene regulatory mechanism that allows cells to significantly diversify their
protein products. Splicing defects, often caused by mutations that disrupt the function of RNA-binding proteins
(RBPs), which regulate splicing, have increasingly been implicated in aging-related disorders including cancer
and neurodegenerative disease. Yet, despite this emerging pattern, few splicing factors have been studied with
regard to aging and aging-related disease. The long-term goal of this project is to begin to elucidate how
aberrant splicing that results from the dysfunction of a highly conserved RBP, leads to abnormal aging
phenotypes. To this end, the highly conserved splicing factor Caper will be used as a model. Caper is required
for the development and maintenance of Drosophila sensory neurons, and for adult locomotor behavior. Our
preliminary data show that caper dysfunction leads to a shortened lifespan and a decline in locomotor behavior
that is exacerbated with age. Moreover, these aging phenotypes show a strong sex bias, where males are
more affected than females. Such sex biases are often seen in aging-related diseases, but the underlying
mechanism for such sex biases remains unknown. Though little is known about the function of the human
caper ortholog, the human caper ortholog, RBM39, is implicated in cancer progression and is expressed
throughout the nervous system. The research proposed within this application will test the following
hypotheses: (1) Caper regulates the maintenance of neurons in the adult brain and nervous system; (2) caper
is differentially spliced in males compared to females; (3) Caper regulates sex-specific splicing during aging.
Using the highly tractable model, Drosophila, we will utilize immunofluorescence to examine various markers of
brain anatomy, apoptosis and mitochondrial markers over time in adult flies to determine if caper dysfunction
results in neurodegeneration. We will use differential gene expression and spliceform analyses to determine
whether caper itself is differentially spliced in aging male versus female flies, and if caper regulates differential
splicing of other genes in aging male versus female flies. Finally, we will perform a pilot genetic screen to
identify genes that interact with caper to regulate aging phenotypes. The outcomes of this study will establish
the foundation for a more comprehensive research program aimed at using caper as a model for aging and sex
biases in aging-related disease. Since aberrant alternative splicing has emerged as a common theme in
various aging disorders, the knowledge gained from this study has broad implications for understanding and
treating such disorders.