Date of Award

Spring 2024

Document Type


Degree Name

Master of Science (MS) in Biology



Committee Chair

Ashley Turner


Hereditary gingival fibromatosis (HGF) is a disease that can present as benign overgrowth of gingival tissue in the mouth. The overgrowth can enclose the entire mouth and teeth in severe cases or present itself in a concentrated area. Researchers have identified that mutations in the SOS1 gene can be responsible for HGF. This disease can impair basic functions related to the mouth. Eating, smiling, speaking can all be affected. Additionally, excess inflammation can cause periodontal disease because of the difficulty in maintaining proper oral health. Periodontal disease can lead to severe bone loss which can lead to complete loss of function of the teeth in the mouth. To further investigate HGF, associated missense variants of uncertain significance (VUS) were analyzed to assess their potential impact on the SOS1 gene through a series of bioinformatics experiments and a comparative study in the C. elegans model system. This project primarily focuses on the potential effects of SOS1 VUS on gene structure and function in human SOS1 and C. elegans sos-1. With the use of Benchling, a VUS was identified in a conserved locus across human, nematode, and 8 other species at SOS1 c.1289A>G (p. Asp430Gly). Additional bioinformatics research was conducted to examine the conservation for additional VUS loci across all clinical classes of significance. PolyPhen-2 was utilized to further analyze the predicted level of damage for each variant. The VUS SOS1 c.1289A>G (p. Asp430Gly) was identified as a likely pathogenic or damaging variant. DNA primers were designed and tested to amplify the VUS region in the C.elegans sos-1 ortholog. Additionally, a single RNA guide was designed to target sos-1, following CRISPR-Cas9 microinjection for future use in experiments. The designed and tested molecular biology reagents will be used in downstream microinjections for creating a CRISPR-Cas9 generated sos-1 VUS mutant strain. This mutant VUS strain will allow for in vivo assessment of potential functional impact to observe if sos-1 mutant VUS nematodes will show a different phenotype compared to N2 wildtype nematodes related to reproductive issues. This project helps shed light on the potential impact of a HGF associated SOS1 VUS through in silico experimentation and aimed to generated reagents to be used in future experiments for further in vivo evaluation in C. elegans.



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