Poster abstracts
Poster number 35 submitted by Mariana Correia
The role of hAGO1 variants in neurodevelopmental disorders
Mariana Correia (The Ohio State University), Nassim Meziane (Sorbonne University), Mira Brazane (Sorbonne University), Amelie Piton (Institute of Genetics, Molecular, and Cellular Biology), Laure Teysset (Sorbonne University), Clement Carre (Sorbonne University)
Abstract:
Neurodevelopmental disorders (NDDs) are defined as impairments in brain function resulting from developmental abnormalities. De novo coding variants in the human AGO genes AGO1 and AGO2 cause NDDs with intellectual disability (ID), referred to as Argonaute syndromes. AGO proteins are central to RNA silencing by associating with small non-coding RNAs (sncRNAs), such as microRNA (miRNAs) and small interfering (siRNAs), to form the RNA-induced silencing complex (RISC). Once assembled, RISC directs AGO to bind target mRNAs, facilitating gene expression regulation through mRNA degradation or translational repression. The project aims to model two NDD-associated hAGO1 variants, F180∆ and G199S in Drosophila melanogaster AGO1 (dAGO1). As a first experimental approach, the host lab generated a Drosophila miRNA overexpression sensor line (mir7-OE) using the inducible expression UAS/GAL4 system. This sensor provides direct insights into dAGO1 dysfunction through its associated wing notch phenotype. We began characterizing the mir7-OE line by crossing it with different UAS RNAi (Knock Down) fly lines for the genes white, Dicer-2, and AGO2, which are not involved in the miRNA-mediated silencing pathway. Various UAS RNAi AGO1 lines were also tested against this tool. The findings concluded the need for further refinement in UAS RNAi AGO1 models to better understand their role in NDDs. In parallel, two human variants were engineered by introducing the corresponding mutations into the fly’s endogenous AGO1 gene using CRISPR/Cas9, a process that is currently ongoing. In continuation of this research, I have joined Dr. Hopper’s Ohio State University laboratory to investigate the newest member of the class of sncRNAs, tRNA introns, using Saccharomyces cerevisiae an organism deficient in RNAi. This research may reveal how tRNA introns evolved as an early form of RNAi, broadening understanding of RNA regulation.
Keywords: neurodevelopmental disorders, argonaute proteins, RNAi