Theses

Date of Award

2026

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

First Advisor

Dr. Peri Kurshan

Second Advisor

Dr. Kristina Ames

Abstract

Messenger RNA (mRNA) plays a crucial role in protein synthesis and cellular processes, important for the development of cells such as neurons. When dysregulation occurs, it can lead to outcomes such as aberrant translation, causing neurodegenerative conditions to arise. Unfortunately, the localization of mRNA in an in vivo cell specific manner is still not understood. To address this, we decided to develop a cell-specific system to image RNA in vivo, within the organism known as C. elegans with a focus on the actin gene. The Actin gene encodes for an important cytoskeleton protein expressed ubiquitously, vital for the cell motility of organisms. To visualize RNA, we implemented a visualization system referred as the MS2 Bacteriophage-MS2 Coat Protein (MS2-MCP) system. This system consists of MS2 stem loops inserted into the 3’Untranslated region (UTR) of the mRNA of interest. The MS2 is bound to MCP fused with a fluorescent protein (FP). A nuclear localization sequence (NLS) fused to the MCP allows sequester unbound MCP-FP within the nucleus, allowing in vivo visualization of mRNA to occur in a spatiotemporal manner. However, it was uncertain if the implementation of this system influenced the function of the Actin gene. To assess this, we decided to focus on a specific set of neurons unique to C. elegans in which actin is responsible for the development of dendritic arbors: Polymodal Somatosensory (PVD) neurons. These neurons have extensive dendritic arbors enveloping the entire body of the C. elegans, making them ideal to determine if the function of the Actin gene (act-4) was affected by the MS2-MCP system. Actin-4 (act-4) strains (with and without) the MS2-MCP system and a PVD marker were generated to assess the PVD neuron morphology and quantified for a more precise result. Our quantification data revealed that there is no significant effect on the function of the act-4 gene with the MS2-MCP system. To standardize our approach for use in different cells, we proceeded to develop a cell-specific system using an inducible system called Flippase-Flippase Recognition Target (FLP-FRT) in which a ubiquitous promoter, pro-1p, drives the expression in a spatiotemporal, and cell-specific manner turning on specific cells. Our findings suggest that using the FLP system with a cell-specific, ubiquitous promoter allows RNA to be expressed at similar levels across cells of interest (specifically in the act-4 MS2 strain) leading to potential research on specific cells (such as different neurons) in C. elegans.

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