29. The Effect of G4 Resolvase 1 (G4R1) on the Transcription of an Abnormal DNA Sequence Linked to ALS

Siara Sandwith Ball State University, Antonio Chambers Ball State University, Adam Richardson Ball State University, Peter Beerbower North Dakota State University
Faculty Sponsor(s): Philip Smaldino Ball State University
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that results in the breakdown of motor neurons, leading to severe deficiencies in eating, breathing, and moving; 80% of all ALS patients succumb to the disease within 5 years of diagnosis. The most common ALS-linked mutation occurs in the C9ORF72 gene (C9), consisting of a GGGGCC-sequence which becomes repeated hundreds to thousands of times, compared to healthy individuals who have <30 repeats. The mutated C9 sequence folds into extensive G-quadruplex (G4) DNA structures, which form within guanine-rich DNA and RNA sequences. G4s generally provide negative regulation on replication, transcription, and translation, while G4-helicases such as G4 Resolvase 1 (G4R1) (aliases: RHAU, DHX36), potentially provide positive regulation on these processes via unwinding G4s. C9-repeat G4-DNA structures are partially unwound and transcribed, and the resulting RNAs form toxic RNA foci that sequester RNA binding proteins. It is unknown if G4R1 binds to the C9-repeat expansion or if it affects C9-repeat transcription. We hypothesize that G4R1 directly binds to and unwinds C9-G4 DNA and increases the transcription of toxic C9-repeat RNAs. To test this, we will express and isolate recombinant G4R1 (rG4R1) and perform gel mobility shift assays with synthetic C9-G4 DNA. Furthermore, we will use a C9-repeat in vitro transcription assay to determine if rG4R1 affects C9-repeat transcription efficiency. Understanding how G4R1 binds to and affects the transcription of the C9-repeat expansion sequence could provide rationale for future experiments, which explore the possibility of targeting G4R1 as a novel C9 ALS therapeutic strategy.
Poster Presentation

When & Where

Irwin Library 3rd Floor