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ABSTRACT
Environmental and genetic factors influence schizophrenia risk. Individuals who have direct family members with schizophrenia have a much higher incidence. Also, acute stress or life crisis may precede the onset of the disease. This study aims to understand the effects of environment on genes related to schizophrenia risk. It investigates the impact of sleep deprivation as an acute environmental stressor on the expression of Htr2a in mice, a gene that codes for the serotonin 2A receptor (5-HT2AR). HTR2A is associated with schizophrenia risk through genetic association studies and expression is decreased in post-mortem studies of patients with the disease. Furthermore, sleep deprivation as a stressor in human trials has been shown to increase the binding capacity of 5-HT2AR. We hypothesize that sleep deprivation will increase the number of cells expressing Htr2a in the mouse anterior prefrontal cortex when compared to controls. Sleep deprived that mice express EGFP under control of the Htr2a promoter displayed anteroposterior gradients of expression across sagittal sections, with concentrations seen most densely within the prefrontal cortex as well as the anterior pretectal nucleus, thalamic nucleus, as well as the cingulate gyrus. Htr2a-EGFP expression was most densely visualized in cortical layer V and VI pyramidal neurons within the lateral prefrontal cortex of coronal sections. Furthermore, the medial prefrontal cortex contained significantly cells expressing Htr2a¬-EGFP than the lateral prefrontal cortex. Ultimately, the hypothesis was not supported and sleep deprivation did not result in more ¬Htr2a-EGFP expressing cells compared to basal levels. However, expressing cells appeared visibly brighter in sleep-deprived animals when compared to controls, indicating that the amount of intracellular Htr2a-GFP expression may be higher. This study provides strong visual representations of expression gradients following sleep deprivation as an acute stressor and paves the way for future studies regarding 5H-T2AR’s role in schizophrenia.
Environmental and genetic factors influence schizophrenia risk. Individuals who have direct family members with schizophrenia have a much higher incidence. Also, acute stress or life crisis may precede the onset of the disease. This study aims to understand the effects of environment on genes related to schizophrenia risk. It investigates the impact of sleep deprivation as an acute environmental stressor on the expression of Htr2a in mice, a gene that codes for the serotonin 2A receptor (5-HT2AR). HTR2A is associated with schizophrenia risk through genetic association studies and expression is decreased in post-mortem studies of patients with the disease. Furthermore, sleep deprivation as a stressor in human trials has been shown to increase the binding capacity of 5-HT2AR. We hypothesize that sleep deprivation will increase the number of cells expressing Htr2a in the mouse anterior prefrontal cortex when compared to controls. Sleep deprived that mice express EGFP under control of the Htr2a promoter displayed anteroposterior gradients of expression across sagittal sections, with concentrations seen most densely within the prefrontal cortex as well as the anterior pretectal nucleus, thalamic nucleus, as well as the cingulate gyrus. Htr2a-EGFP expression was most densely visualized in cortical layer V and VI pyramidal neurons within the lateral prefrontal cortex of coronal sections. Furthermore, the medial prefrontal cortex contained significantly cells expressing Htr2a¬-EGFP than the lateral prefrontal cortex. Ultimately, the hypothesis was not supported and sleep deprivation did not result in more ¬Htr2a-EGFP expressing cells compared to basal levels. However, expressing cells appeared visibly brighter in sleep-deprived animals when compared to controls, indicating that the amount of intracellular Htr2a-GFP expression may be higher. This study provides strong visual representations of expression gradients following sleep deprivation as an acute stressor and paves the way for future studies regarding 5H-T2AR’s role in schizophrenia.
ContributorsSchmitz, Kirk Andrew (Author) / Gallitano, Amelia (Thesis director) / Stout, Valerie (Committee member) / Maple, Amanda (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
The Dorrance Center for Rare Childhood Disorders is a unique research division at TGen (The Translational Genomics Research Institute) that provides personalized care to children and young adults facing rare, undiagnosed diseases. TGen scientists believe that the answers to these enigmatic disorders can often be found in a person's genetic code. They aim to solve these genetic mysteries using whole exome sequencing, a method that prioritizes the protein-coding portion of the genome in the search for disease-causing variants. Unfortunately, a communication gap sometimes exists between the TGen scientists and the patients they serve. I have seen, first hand, the kind of confusion that this study elicits in the families of its participants. Therefore, for my thesis, I decided to create a booklet that is meant to provide some clarity as to what exactly The Dorrance Center for Rare Childhood Disorders does to help diagnose children with rare disorders. The purpose of the booklet is to dispel any confusion regarding the study by providing a general review of genetics and an application of these lessons to the relevant sequencing technology as well as a discussion of the causes and effects of genetic mutations that often times are linked to rare childhood disorders.
ContributorsCambron, Julia Claire (Author) / LaBelle, Jeffrey (Thesis director) / Huentelman, Matt (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Duchenne Muscular Dystrophy (DMD) is an X-linked recessive disease characterized by progressive muscle loss and weakness. This disease arises from a mutation that occurs on a gene that encodes for dystrophin, which results in observable muscle death and inflammation; however, the genetic changes that result from dystrophin's dysfunctionality remain unknown. Current DMD research uses mdx mice as a model, and while very useful, does not allow the study of cell-autonomous transcriptome changes during the progression of DMD due to the strong inflammatory response, perhaps hiding important therapeutic targets. C. elegans, which has a very weak inflammatory response compared to mdx mice and humans, has been used in the past to study DMD with some success. The worm ortholog of the dystrophin gene has been identified as dys-1 since its mutation phenocopies the progression of the disease and a portion of the human dystrophin gene alleviates symptoms. Importantly, the extracted RNA transcriptome from dys-1 worms showed significant change in gene expression, which needs to be further investigated with the development of a more robust model. Our lab previously published a method to isolate high-quality muscle-specific RNA from worms, which could be used to study such changes at higher resolution. We crossed the dys-1 worms with our muscle-specific strain and demonstrated that the chimeric strain exhibits similar behavioral symptoms as DMD patients as characterized by a shortened lifespan, difficulty in movement, and a decrease in speed. The presence of dys-1 and other members of the dystrophin complex in the body muscle were supported by the development of a resulting phenotype due to RNAi knockdown of each component in the body muscle; however, further experimentation is needed to reinforce this conclusion. Thus, the constructed chimeric C. elegans strain possesses unique characteristics that will allow the study of genetic changes, such as transcriptome rearrangements and dysregulation of miRNA, and how they affect the progression of DMD.
ContributorsNguyen, Thuy-Duyen Cao (Author) / Mangone, Marco (Thesis director) / Newbern, Jason (Committee member) / Duchaine, Thomas (Committee member) / School of Social Transformation (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
ContributorsSavarese, Erica (Author) / Robert, Jason (Thesis director) / Hurlbut, Ben (Committee member) / Verrelli, Brian (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
It is important to consider factors that contribute to successful fertilization and the development of viable offspring. Better understanding the factors that contribute to infertility can be used to assist in the development of viable offspring, especially for human beings looking to successfully reproduce. Identifying paternal effect genes, genes that come from the father, introduces more targets that can be manipulated to produce specific reproductive effects. Use of Drosophila melanogaster as a model to study reproduction has increased, in part, due to the use of the GAL4 system. In this system, the GAL4 gene encodes an 881 amino acid protein that binds to the 4-site Upstream Activating Sequence (UAS) to induce transcription of the gene of interest. These sequences constitute the two components of the system: the driver (GAL4) and the responder (gene of interest) \u2014 each of which is maintained as a separate parental line. Effects of the GAL4 driver line "driving" transcription of the responder can be assessed by examining the offspring. One of the more common uses of the GAL4 system involves analyzing phenotypic effects of reducing or eliminating expression of a target gene through the induction of RNAi transcription, which often results in toxicity, lethality, or reduced viability. Utilizing these principles, we strove to demonstrate the effect of knocking down the expression of testis-specific sperm-leucyl-aminopeptidases gene CG13340 on progeny by inducing expression of RNAi with two distinct GAL4 driver lines - one with a nonspecific actin-binding activation sequence and the other with a testis-specific activation sequence. Comparison of both GAL4 driver lines to crosses using N01 wild type ("wt") flies verify that inducing RNAi transcription using the GAL4 system results in reduction of proper offspring development. Further studies using D. melanogaster and the GAL4 system can improve knowledge of factors contributing to male fertility and also be applied to better understand mammalian, specifically human, fertility.
ContributorsEvans, Donna Marie (Author) / Karr, Timothy L. (Thesis director) / Roland, Kenneth (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / Department of English (Contributor)
Created2014-05
Description
Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is a devastating illness that causes the degeneration of both upper and lower motor neurons, leading to eventual muscle atrophy. ALS rapidly progresses into paralysis, with patients typically dying due to respiratory complications within three to five years from the onset of their symptoms. Even after many years of research and drug trials, there is still no cure, and current therapies only succeed in increasing life-span by approximately three months. With such limited options available for patients, there is a pressing need to not only find a cure, but also make new treatments available in order to ameliorate disease symptoms. In a genome-wide association study previously conducted by the Translational Genomics Research Institute (TGen), several single-nucleotide polymorphisms (SNPs) upstream of a novel gene, FLJ10968, were found to significantly alter risk for ALS. This novel gene acquired the name FGGY after publication of the paper. FGGY exhibits altered levels of protein expression throughout ALS disease progression in human subjects, and detectable protein and mRNA expression changes in a mouse model of ALS. We performed co-immunoprecipitation experiments coupled with mass spectrometry in order to determine which proteins are associated with FGGY. Some of these potential binding partners have been linked to RNA regulation, including regulators of the splicesomal complex such as SMN, Gemin, and hnRNP C. To further validate these findings, we have verified co-localization of these proteins with one another. We hypothesize that FGGY plays an important role in ALS pathogenesis, and we will continue to examine its biological function.
ContributorsTerzic, Barbara (Author) / Jensen, Kendall (Thesis director) / Francisco, Wilson (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
The NCAA recently declared sickle cell trait (SCT) to be a risk factor for sudden illness and death among student athletes. Fetal hemoglobin (HbF) concentration in adults is negatively correlated with disease severity in sickle cell anemia, although its effect on SCT is not fully understood and the concentration is found to have high variability across populations. Two single nucleotide polymorphisms (SNPs) at the human beta globin gene cluster, rs7482144 and rs10128556, contribute to the heritable variation in HbF levels and are associated with increased HbF concentrations in adults. A sample population of NCAA football student athletes was genotyped for these two polymorphisms, and their allele frequencies were compared to those of other populations. The minor allele of both polymorphisms had allele frequencies of 0.091 in the sample population, which compared closely with other populations of recent African heritage but was significantly different from European populations. The results of this study will be included in a larger study to predict whether these among other polymorphisms can be used as markers to predict susceptibility to heat-related emergencies in NCAA student athletes with SCT, although the small sample size will delay this process until participation in the study increases. Since both rs7482144 and rs10128556 exhibit high levels of linkage disequilibrium, and as their contributions to the heritable variability of HbF concentrations tend to differ greatly between populations of different ancestry, further investigations should be aimed at distinguishing between the effects of each SNP in African American, European, and other populations represented in NCAA football before conclusions can be drawn as to their practical use as genetic markers of heat susceptibility in student athletes with SCT.
ContributorsGrieger, Ryan Wayne (Author) / Stone, Anne C. (Thesis director) / Rosenberg, Michael (Committee member) / Madrigal, Lorena (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
The knowledge of medical genetics is currently used with prenatal testing, and the advancements in the field of behavioral genetics may someday allow for its use with prenatal testing as well. The use of prenatal procedures for medical phenotypes has its own implications and should these techniques be used for behavioral phenotypes, such implications can also apply. The complexity of behavior in terms of the factors that may affect it, along with the way it is conceptualized and perceived, adds further implications for prenatal testing of it. In this thesis, I discuss the qualitative, quantitative, and historical facets of prenatal testing for medical and behavioral phenotypes and the undercurrent of eugenics. I do so by presenting an example of the medical phenotype (cystic fibrosis) as a case for envisioning the implications of medical phenotypes before delving into examples of behavioral phenotypes (aggression, impulsivity, extraversion, and neuroticism) in order to explore the implications shared with those for medical phenotypes as well as those unique to it. These implications then set the foundation for a discussion of eugenics, and the considerations for how behavioral genetics with prenatal testing may give way to a modern form of it.
ContributorsMinai, Mandana (Author) / Maienschein, Jane (Thesis director) / Robert, Jason (Committee member) / Magnus, David (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / Department of Psychology (Contributor)
Created2014-05
Description
An introduction to neuroscientific thought aimed at an audience that is not educated in biology. Meant to be readable and easily understood by anyone with a high school education. The first section is completed in its entirety, with outlines for the proposed final sections to be completed over the next few years.
ContributorsNelson, Nicholas Alan (Author) / Olive, M. Foster (Thesis director) / Brewer, Gene (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor)
Created2014-05
Description
Esophageal adenocarcinoma (EAC) is one of the most lethal and fastest growing cancers in the United States. Its onset is commonly triggered by metaplastic transformation of normal squamous esophageal epithelial cells to Barrett's esophagus (BE) cells in response to acid reflux. BE patients are believed to progress through non-dysplastic metaplasia and increasing grades of dysplasia prior to EAC. Conventional cancer diagnostic tools rely on bulk-cell analyses that are incapable of identifying intratumoral heterogeneity or rare driver cells that play important roles in cancer progression. An improved single-cell method of cancer diagnosis would overcome this challenge by detecting cancer initiating cells before they progress into untreatable stages. In this study, using EAC as a model, we attempted to identify a more effective method of cancer diagnosis. We quantified the single- and bulk-cell mRNA expression of genes that have been proposed to be instrumental in the progression of EAC through BE. Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) analysis was performed on human primary cells to measure the mRNA expression levels of BE- and EAC-associated genes. Our results showed high levels of heterogeneity of CDX2 and TFF3 at the single-cell resolution in human BE and EAC samples. Additionally, while expression of VEGF is generally low at the bulk-cell level, our results showed that a few, rare cells had significantly higher VEGF expression levels than the majority of cells in the EAC sample. In conclusion, we have affirmed that EAC cancer cells, as well as BE cells, show high levels of heterogeneity. Based on the VEGF gene expression pattern, single-cell analysis could potentially be more effective for identifying rare, but essential cells for cancer progression, which could then be targeted for treatment. Future studies will focus on analyzing human samples from thousands of normal and cancer subjects to validate the use of single-cell profiling in cancer.
ContributorsHaeuser, Kelsey Lynn (Author) / Tran, Thai (Thesis director) / Kelbauskas, Laimonas (Committee member) / Gao, Weimin (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-12