Abstract
Two proteins implicated in ALS in humans are TDP-43 and FUS. This project studied the impact of the overexpression of TDP-43 and knockdown of the fly homolog of FUS, Cabeza, on abundant circular RNAs (circRNAs) in D. melanogaster, in search of potential connections between the expression of these genes and neurodegenerative diseases. circRNAs are hyperstable, noncanonical backsplicing products that accumulate with age, but little is known about their relationship with ALS. To monitor expression levels, RNA was isolated from fly heads and quantified through RT-qPCR. These flies were modified in two ways: a humanized TDP-43 (hTDP-43) gene was introduced and overexpressed using a drug-inducible system; normal expression of cabeza in flies was disrupted using RNA interference (RNAi). The highly-conserved gene muscleblind (mbl), which is responsible for myotonic dystrophy, could possibly be linked to ALS as well; a complementation assay of flies with mutated mbl alleles was completed to better understand the relationship between mbl, FUS, and TDP-43 in connection to neurodegenerative outcomes. The data indicate a connection between TDP-43 and the abundant circRNAs PlexA and Haspin, and a connection between Cabeza and circRNA Haspin, indicating these circRNAs could be involved with ALS. The complementation assay showed that at least one functional copy of mbl is necessary for survival. These results contribute to the exploratory study of circRNAs, and lay the groundwork for future, specific study of TDP-43 and FUS/Cabeza in relation to the nervous system and its disorders in humans.