Molecular Genetics Commons^™

How To Measure, Analyze, And Interpret Age-Related Changes In Caenorhabditis Elegans: Lessons For Mechanistic And Evolutionary Theories Of Aging, Zuzana Kocsisova, Brian M. Egan, Andrea Scharf, Xavier Anderson, Franziska Pohl, Aaron Anderson, Kerry Kornfeld

Biological Sciences Faculty Research & Creative Works

Aging is characterized by progressive degenerative changes in tissue organization and function, some of which increase the probability of mortality. Major goals of aging research are to elucidate the series of events that cause degenerative changes, and to identify environmental, pharmacological, and genetic factors that influence these changes; this information might lead to new strategies to extend health span and lifespan. Mechanistic studies of aging depend on accurate and precise descriptions of age-related changes, since these descriptions define the aging phenotype. Here, we review studies that describe age-related changes in C. elegans, including measurements of integrated functions such as behavior …

Building A Cell Specific System For In Vivo Rna Imaging Of The Endogenous Actin Gene In C. Elegans, Jasmine A. Huerta Canete

Theses and Dissertations

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 …

Rnai Pathway Homeostasis Is Essential For Longevity In C. Elegans., Sejal Dulal

2025 Spring Honors Capstone Projects - Archive

RNA interference (RNAi) is a gene regulatory mechanism that is conserved across all animal species, including humans and the microscopic nematode, Caenorhabditis elegans. Many studies have identified the RNAi pathway factors and dissected the regulatory mechanisms of RNAi pathways, but there is little understanding of how the RNAi pathways themselves are regulated. Previously, Rogers and Phillips identified a feedback loop mediated by a pair of small RNA sensors, Sensor of siRNAs-1 (sosi-1) and eri-6[e-f], embedded within the genomic locus of a small RNA biogenesis factor, ERI-6/7. In this feedback motif, loss of small RNA-mediated silencing of …

Developing A Small Molecule To Inhibit Hsf1 Expression In Cancer And Evaluating Natural Genetic Variation In Small Molecule Toxicity., Michaela Kendal Foley

Theses and Dissertations

Each year cancer affects nearly 20 million people worldwide and genetic differences across populations can impact cancer onset and progression. Specifically, tumors with high levels of HSF1, the master regulator of the cytoprotective heat shock response (HSR), are correlated with poor patient outcomes in multiple cancers such as prostate, breast, and melanoma. Subsequently, the development of pharmacological inhibitors of HSF1 represents a promising strategy for anticancer therapeutics. Using a luciferase-based transcriptional reporter, two small molecule libraries were screened for inhibitors of HSF1 expression in human embryonic kidney cells, yielding ten compounds that decrease HSF1 expression. To identify if cancer lines …

Gonadal Absence Of Ceh-22: Degradation Of Ceh-22 In The Gonads Of Caenorhabditis Elegans, Andreya C. White

Undergraduate Theses

The reproductive system of hermaphrodite Caenorhabditis elegans (C. elegans) comprises two gonadal arms, each with a terminating distal tip cell (DTC), connected by a common uterus. The DTC has two functions: leader and niche. In C. elegans, ceh-22/nkx2,5 has been found to work together with Wnt signaling to determine the fates of the DTC (Lam et al., 2006). This is an indication that ceh-22 aids in the specification of DTCs. Our research aims to determine the specific function of ceh-22 in the gonad of both male and hermaphrodite C. elegans. This will be accomplished by observing …

Exploring The Functional Significance Of A Yap1 Missense Variant Of Uncertain Significance In Caenorhabditis Elegans, Nathan Jones

Theses

Polycystic ovary syndrome (PCOS) is a complex disorder with various implications, such as polycystic ovaries, visceral obesity, and increased risk of cancer. YAP1 was recently identified as a gene of interest in the development of PCOS. Researchers have established that single nucleotide variants in YAP1 are likely to play a role in PCOS development. This project aims to provide insight into the potential impact of a YAP1 variant of uncertain significance (VUS). Studies in C. elegans have established yap-1 as a nematode ortholog for human YAP1. A YAP1 VUS was identified through ClinVar, YAP1 c.1015A>G (p.Asn339Asp). Evolutionary conservation …

A Comparative Study Of A Non-Small Cell Lung Cancer Associated Egfr Missense Variant Of Uncertain Significance, Vanessa Mejia

Theses

Non-small cell lung cancer (NSCLC) is a form of lung cancer that can be driven by heightened activity of epidermal growth factor receptor encoded by the EGFR gene. Genetic variants in EGFR have been identified that lead to abnormal cell growth and tumorigenesis. The objectives of this study was to 1) determine if an EGFR variant of uncertain significance (VUS) associated with NSCLC is potentially damaging based on evaluation of the ortholog let-23 in the model organism, C. elegans, and 2) identify conserved missense VUS loci associated with NSCLC. Through ClinVar, the EGFR VUS c.845G>C(p.Gly282Ala) was identified in …

Engaging Students In A Genetics Course-Based Undergraduate Research Experience Utilizing Caenorhabditis Elegans In Hybrid Learning To Explore Human Disease Gene Variants, Natalie Forte, Virginia Veasey, Bethany Christie, Amira Carter, Marli Hanks, Alan Holderfield, Taylor Houston, Anil Challa, Ashley Turner

Research, Publications & Creative Work

Genetic analysis in model systems using bioinformatic approaches provides a rich context for a concrete and conceptual understanding of gene structure and function. With the intent to engage students in research and explore disease biology utilizing the nematode Caenorhabditis elegans model, we developed a semester-long course-based undergraduate research experience (CURE) in a hybrid (online/in-person) learning environment—the gene-editing and evolutionary nematode exploration CURE (GENE-CURE). Using a combination of bioinformatic and molecular genetic tools, students performed structure-function analysis of disease-associated variants of uncertain significance (VUS) in human orthologs. With the aid of a series of workshop-style research sessions, students worked in teams …

Orthologs Of The C. Elegans Heterochronic Genes Have Divergent Functions In C. Briggsae, Maria Ivanova, Eric G. Moss

Rowan-Virtua Research Day

The heterochronic genes of C. elegans comprise the best-studied pathway controlling the timing of tissue and organ formation in an animal. To begin to understand the evolution of this pathway, the significance of each factor, and the relationships among the components, we characterized 11 C. briggsae orthologs of C. elegans heterochronic genes. Using CRISPR/Cas9, we made a variety of alleles and found that several mutant phenotypes differ in significant ways from those of C. elegans. Although most orthologs displayed defects in developmental timing, those phenotypes could differ in which stages they controlled, the penetrance and expressivity of the phenotypes, or …

Dual Mechanisms Implemented By Lin-28 For Positive Regulation Of Hbl-1 Are Necessary For Proper Development Of Distinct Tissues In Caenorhabditis Elegans, Madeleine Minutillo

Graduate School of Biomedical Sciences Theses and Dissertations

In Caenorhabditis elegans, the heterochronic pathway is comprised of a hierarchy of genes that control the proper timing of developmental events. hbl-1 (Hunchback Like-1) encodes an Ikaros family zinc-finger transcription factor that promotes the L2 stage cell fate events of the hypodermis. The downregulation ofhbl-1 is a crucial step for the transition from the L2 to the L3 stage. There are two known processes through which negative regulation of hbl-1 occurs: suppression of hbl-1 expression by 3 let-7 miRNAs through the hbl-1 3’UTR and inhibition of HBL-1 activity by LIN-46. The mechanisms by which hbl-1 is positively regulated have not …

Evolutionary Conservation Of The Heterochronic Pathway In C. Elegans And C. Briggsae, Maria Ivanova, Eric G. Moss

Rowan-Virtua Research Day

Heterochronic genes control the sequence and timing of developmental events during four larval stages of Caenorhabitis nematodes. Mutations in these genes may cause skipping or reiteration of developmental events.

C. briggsae is a close relative of C. elegans. These species have similar morphology and share the same ecological niche. C. briggsae undergoes the same developmental pathway consisting of four larval stages before reaching adulthood. It also has the same set of heterochronic genes.

Lin-28 is one of the heterochronic genes that also exists in other animals from flies to humans. It conservatively blocks the maturation of let-7 miRNA, the process …

Analyzing The Effect Of Apoptotic Mutations On The State Of The Nascent-Polypeptide Associated Complex In Caenorhabditis Elegans, Monica Gerber

Senior Honors Projects, 2010-2019

Cells experiencing misfolded protein stress can become debilitated and die, contributing to the onset of disease. The nascent polypeptide-associated complex (NAC) is a heterodimeric translational chaperone that protects against misfolded protein stress by mediating proper protein folding and localization during translation. Depletion of this complex results in misfolded protein accumulation in the endoplasmic reticulum (ER). To determine the importance of the NAC to proteostasis, we have previously depleted the complex in C.elegans via RNA interference and observed numerous dose-dependent effects, including apoptosis of neuronal cells and changes in gene expression of hypodermal cells. While we have observed these cell-specific responses …

Times Of Action And Evolutionary Conservation Of Heterochronic Genes, Maria Ivanova, Eric G. Moss

Rowan-Virtua Research Day

Specific genes called heterochronic genes control the timing and sequence of developmental events during larval stages of C. elegans. Mutations in heterochronic genes can cause skipping or reiteration of cell fates associated with certain larval stages. lin-14 and lin-28 are two well-studied heterochronic genes. LIN-14 acts during the first larval stage (L1) and controls events of the L1 and L2 stages, LIN-28 acts during the L2 stage and controls its events.

Platiscity Of C. Elegans Germline Stem Cells Under Nutritional And Metabolic Stress, Kenneth Trimmer

Dissertations and Theses (Open Access)

Stem cells are integral for tissue maintenance and fertility. Therefore, understanding how stem cells are regulated under stress is imperative. When confronted with acute starvation, stem cells must conserve energy and metabolites to cope with the lack of an external source. Caenorhabditis elegans germline stem cells (GSCs) are an excellent model for studying stem cell properties and regulation as they can divide throughout the life of the organism. While GSCs are an adult stem cell population, their cell cycle structure more closely mimics mouse and human embryonic stem cells with short G1 and long S phases. In this thesis, I …

Phenotypic Characterization Of Pnpase Mutation And Overexpression In C. Elegans, Brian J. Hur

Theses and Dissertations

PNPase, polynucleotide phosphorylase, is a multifunctional exoribonuclease protein with 3` terminal oligonucleotide polymerase activity. Coded by the PNPT1 gene, the protein is associated with mitochondrial homeostasis and functions as a possible target for cancer therapy. In this study, C. elegans was used to investigate the effect of mutation and overexpression of pnpt-1, the gene that encodes PNPase. It was determined that two specific mutations in pnpt-1 did not affect PNPase expression nor did they produce deleterious phenotypes that affected polycistronic transcript accumulation or ROS production. Creation of a stable overexpression model was achieved through Fusion PCR. However, different transgenic …

Loss Of Function Of Gene X Protects Against Α-Dicarbonyl Stress Through The Skn-1 Pathway In C. Elegans, Austin Lim

Dissertations, Masters Theses, Capstones, and Culminating Projects

Diabetes mellitus and Parkinson’s Disease (PD) are debilitating diseases that are increasing in prevalence worldwide. One potential cause of these diseases is the accumulation of advanced glycation end products (AGEs), which are macromolecules that cause irreversible damages. AGEs are a diverse group of highly oxidative byproducts produced from α-dicarbonyl compounds (α-dcs), which are highly reactive molecules that bind indiscriminately to protein and DNA and, are regulated by a conserved glyoxalase system (GLO1 and DJ-1) in humans. Utilizing the conserved glyoxalase system, we were able to establish within a C. elegans model that when this glyoxalase system is impaired, …

Role Of Mitochondrial Beta-Oxidation In Ethanol Response: A Candidate Gene Study Using Caenorhabditis Elegans, Harini Pallikarana Tirumala

Theses and Dissertations

Alcohol use disorder (AUD) is the fourth leading cause of preventable death in the United States, and the fifth leading risk factor for premature death and disability, globally. There are currently very few treatment options for AUD and there is a need for effective preventive and treatment strategies for this condition. AUD risk has a significant hereditary component, with the contribution of genetic factors being estimated to be about 50%. The Davies-Bettinger laboratory uses C. elegans as a model organism to study the contribution of genetic factors in modulating neuronal responses to ethanol. In this project, we examined the role …

Pnpase In C. Elegans: Mutagenic Analysis To Complement Knockdown Studies, Danielle K. Seibert

Theses and Dissertations

PNPase is a gene implicated as a potential target for cancer therapy; human mutations also present with deafness, myopathies, and neuropathies. In this study, C. elegans was used to investigate the effect of knocking out PNPase in a whole animal. C. elegans knockdown studies have reported an extended lifespan via an increase in ROS production. Further noted are larger mitochondria and an increase in fzo-1 expression. Knockout animals previously constructed using CRISPR/Cas9 were used for this study. We aimed to confirm these findings validating previous studies. It was discovered that PNPase knockout animals demonstrated a similar lifespan extension that was …

Activation Of Target Gene Expression In Neurons By The C. Elegans Rfx Transcription Factor, Daf-19, Katherine P. Mueller

Lawrence University Honors Projects

DAF-19, the only RFX transcription factor found in C. elegans, is required for the formation of neuronal sensory cilia. Four isoforms of the DAF-19 protein have been reported, and the m86 nonsense (null) mutation affecting all four isoforms has been shown to prevent cilia formation. Transcriptome analyses employing microarrays of L1 and adult stage worms were completed using RNA from daf-19(m86) worms and an isogenic wild type strain to identify additional putative DAF-19 target genes. Using transcriptional fusions with GFP, we compared the expression patterns of several potential gene targets using fluorescence confocal microscopy. Expression patterns were characterized in …

The Thioredoxin Trx-1 Regulates The Major Oxidative Stress Response Transcription Factor, Skn-1, In Caenorhabditis Elegans, Katie C. Mccallum

Dissertations and Theses (Open Access)

The ability to respond to hostile environmental conditions is critical for the survival of an organism. Oxidative stress is an adverse state in which reactive oxygen species (ROS) accumulate to a harmful level and, if left unresolved, can lead to cellular dysfunction and organismal disease. Sophisticated detoxification systems, characterized by a battery of enzymatic antioxidants, are utilized to neutralize ROS thereby reducing stress. However, ROS are also purposefully produced by designated cellular enzymes to facilitate the signaling and regulation of critical physiological processes. Therefore, both the production and neutralization of ROS must be tightly controlled. Indeed, the expression of detoxification …

Reactive Oxygen Species-Mediated Neurodegeneration Is Independent Of The Ryanodine Receptor In Caenorhabditis Elegans, Lyndsay E.A. Young, Daniel C. Williams

Journal of the South Carolina Academy of Science

Despite the significant impacts on human health caused by neurodegeneration, our understanding of the degeneration process is incomplete. The nematode Caenorhabditis elegans is emerging as a genetic model organism well suited for identification of conserved cellular mechanisms and molecular pathways of neurodegeneration. Studies in the worm have identified factors that contribute to neurodegeneration, including excitotoxicity and stress due to reactive oxygen species (ROS). Disruption of the gene unc-68, which encodes the ryanodine receptor, abolishes excitotoxic cell death, indicating a role for calcium (Ca²⁺) signaling in neurodegeneration. We tested the requirement for unc-68 in ROS-mediated neurodegeneration using the …

Genome Engineering To Create Dominant Alleles In Caenorhabditis Elegans Using Crispr-Cas9 Technology, Abrar Sulaimani

Graduate School of Biomedical Sciences Theses and Dissertations

Many investigators have being using CRISPR-Cas9 as a method of genome engineering because it is easy, accurate and fast. This technique has been used to modify the genomes of a wide variety of organisms, including the nematode Caenorhabditis elegans (C. elegans). The short life cycle and ease of introducing exogenous plasmids make C. elegans an ideal system for advancing this technique. My thesis had two aims that focused on developing methods to create dominant alleles in C. elegans. Genetic modifications like precise deletion and insertions into a locus of chromosome are technically challenging. Additionally, although there are several ways of …

Profile Of The Unfolded Protein Response In C. Elegans Depleted Of The Translational Chaperone, Nac., Caylin S. Murray

Masters Theses, 2010-2019

The function of a protein is a direct consequence of its final structure, which is achieved by protein-folding processes that generate a tertiary state through the juxtaposition of locally formed secondary structures. Because all cells need functional proteins to survive, each contains robust and redundant mechanisms that regulate the folding of newly forming proteins, and the refolding of misfolded proteins that are often generated during stress. Essential to these mechanisms, chaperones are proteins that aid in protein folding of nascent and misfolding protein without being incorporated in the final structure. One chaperone complex, the nascent polypeptide-associated complex (NAC), aids in …

Potential Roles Of Peroxidases In Caenorhabditis Elegans Innate Immunity, George R. Tiller, George R. Tiller

Dissertations and Theses (Open Access)

The production of ROS (reactive oxygen species) in response to pathogen detection is a rapid, nonspecific response that is evolutionarily conserved from nematodes to humans. ROS serve as direct and indirect effectors of innate and adaptive immunity. In Caenorhabditis elegans, a ROS burst is observed during infection and is mediated by the dual oxidase BLI-3, which produces H₂O₂. RNAi (RNA interference) to reduce the amount of BLI-3 results in a significant increase in susceptibility to pathogens, suggesting BLI-3 has a role in the immune response. However, H₂O₂ by itself is not a …