Molecular and Cellular Neuroscience Commons^™

Structural And Functional Consequences Of Pde6 Prenylation In Rod And Cone Photoreceptors, Faezeh Moakedi

Graduate Theses, Dissertations, and Problem Reports

Phosphodiesterase-6 (PDE6) serves as a pivotal component in the phototransduction pathways of both cone and rod photoreceptors. In cones, PDE6 consists of tetrameric subunits: inhibitory (γ') and catalytic (α'). The catalytic subunit, PDE6α', contains a C-terminal prenylation motif. Deletion of this motif is associated with achromatopsia (ACHM), a form of color blindness. The mechanisms underlying the disease and the roles of PDE6 lipidation in vision remain elusive. Meanwhile, rod PDE6 is composed of α and β catalytic subunits and γ inhibitory subunits, with alterations in the C-terminal "prenylation motif" of PDE6β linked to retinitis pigmentosa (RP) pathology. In this comprehensive …

Characterization Of Pathological Tau Mutants, Charles J. Mcdonald

Dissertations, Theses, and Capstone Projects

Tau is a protein expressed exclusively in glia and neurons in the central nervous system and implicated in several neurogenerative diseases called “tauopathies”. Among all the tauopathies, one third is characterized by the presence of genetic mutations leading to the synthesis of tau proteins with single amino acid substitutions at specific locations and affecting protein function. While most of the initial studies have emphasize the functional role of tau as modulator of the axonal cytoskeleton, it has recently been well accepted that tau is also an intrinsically disordered protein that tends to form membraneless organelles called coacervates, due to a …

The Role Of Parkin In Mitochondrial Dna, Eliezer Lichter

Theses & Dissertations

Mitochondria are at the center of biological phenomena such as aging and diseases, especially neurodegenerative diseases. While the discovery of mitochondria only came approximately 200 years after the cell was discovered, a lot of progress has been made since. The mitochondrial genome encodes proteins vital for mitochondrial function. These proteins are only a subset of the proteins present in mitochondria; the rest are nuclear encoded. The nucleus also encodes cytosolic proteins vital for mitochondrial maintenance. One of these is Parkin, an E3 ubiquitin ligase that ubiquitinates mitochondrial proteins as mitochondria become depolarized. Its activity has been shown to be involved …

Chemosensory Receptors In Berghia Stephanieae: Bioinformatics And Localization, Kelsi L. Watkins

Masters Theses

Chemosensation is achieved through the binding of chemical signals to chemoreceptor proteins embedded in the membranes of sensory neurons. The molecular identity of these receptors, as well as the downstream processing of chemosensory signals, has been well studied in arthropods and vertebrates. However, very little is known about molluscan chemosensation. The identity of chemoreceptor proteins in the nudibranch mollusc Berghia stephanieae are unknown. Data from other protostome and molluscan studies suggest Berghia may use ionotropic receptors for some forms of chemoreception. This study used a bioinformatics approach to identify potential chemosensory ionotropic receptors in the transcriptome of Berghia. A …

The Effects Of Deletion Of The Cytoplasmic Domain Of Robo3 On Drosophila, Jessie Agcaoili

Biological Sciences Undergraduate Honors Theses

My research project examines how the deletion of the cytoplasmic domain affects the function of Robo3. If Robo3 is signaling repulsion in response to SLIT this activity should require the cytoplasmic domain. I investigated the functional importance of Robo3 by deleting the cytoplasmic domain of Robo3 using a CRISPR-based technique. This modified gene was then injected into Drosophila embryos where it replaced the normal copy of the gene. Embryos expressing the modified version of robo3 in place of normal robo3 were dissected and examined.

Examining Development And Function Of Pretectal Visual Neural Circuits In Gs Homeobox 1 Mutant Zebrafish, Alexandra Rose Schmidt

Graduate Theses, Dissertations, and Problem Reports

Brain development requires a coordinated genetic code to regulate initial cell identity determination, migration, and connectivity, to establish function of neural circuits. Independent neural circuits underlie our ability to produce both complex and innate behavioral responses to sensory stimuli that are often conserved across vertebrate organisms. Sensory processing disruptions are associated with several neurodevelopmental disorders (NDDs). Therefore, gene mutations altering neurodevelopment can lead to changes influencing structure and function of individual neural circuits, causing behavioral deviations in sensory responsiveness. Crucial gene networks that define functional properties of sensory domains are often explored using non-mammalian vertebrate models, such as the zebrafish. …

Deciphering The Role Of Hsp110 Chaperones In Diseases Of Protein Misfolding, Unekwu M. Yakubu

Dissertations & Theses (Open Access)

Molecular chaperones maintain protein homeostasis (proteostasis) by ensuring the proper folding of polypeptides. Loss of proteostasis has been linked to the onset of numerous neurodegenerative disorders including Alzheimer’s, Parkinson’s, and Huntington’s disease. Hsp110 is a member of the Hsp70 class of molecular chaperones and acts as a nucleotide exchange factor (NEF) for Hsp70, the preeminent Hsp70-family protein folding chaperone. Hsp110 promotes rapid cycling of ADP for ATP, allowing Hsp70 to properly fold nascent or unfolded polypeptides in iterative cycles. In addition to its NEF activity, Hsp110 possesses an Hsp70-like substrate binding domain (SBD) whose biological roles are undefined. Previous work …

Having A High-Activity Catechol-O-Methyltransferase Allele Is Associated With Elevated Anxiety And Lower Salivary Dehydroepiandrosterone But Also Lower Alpha Amylase In Children With Chromosome 22q11.2 Deletion Syndrome., Jessie Beebe

University of New Orleans Theses and Dissertations

Chromosome 22q11.2 deletion syndrome (22q11.2DS) results from a hemizygous deletion located on the long arm of chromosome 22. The most common deletion sizes affect between 30 and 90 genes. Individuals with 22q11.2DS may develop serious developmental and psychiatric disorders. The phenotype is highly variable, however, and may be influenced by allelic variation of the retained copies of genes covered by the deletion. I set out to examine the effects of two genes, catechol-O-methyltransferase (COMT) and proline dehydrogenase (PRODH), in relation to anxiety in children and adolescents with 22q11.2DS. Individuals with the major COMT allele (higher activity) have significantly higher anxiety …

Translational Fidelity And Its Role In Neuronal Homeostasis, Markus Terrey

Electronic Theses and Dissertations

The process of translation, which refers to decoding genetic information from mRNA to protein, is vital for all cellular function. Translational fidelity starts at the level of aminoacylation of transfer RNAs (tRNA). This reaction is catalyzed by aminoacyl tRNA synthetases where each amino acid is transferred to its corresponding cognate tRNA. Because tRNAs harbor the anticodon sequence to decodes a particular mRNA codon, the specific aminoacylation of the tRNA with a cognate amino acid establishes the rules of decoding genetic code into proteins. Aminoacylated tRNAs are then delivered to ribosomes, where ribosomes in a highly organized manner need to accurately …

Cloning And Functional Characterizations Of Circular Rnas From The Human Mapt Locus, Justin R. Welden

Theses and Dissertations--Molecular and Cellular Biochemistry

Under pathophysiological conditions, the microtubule protein tau (MAPT) forms neurofibrillary tangles that are the hallmark of sporadic Alzheimer’s disease as well as familial frontotemporal dementias linked to chromosome 17 (FTDP-17). In this work, I report that MAPT forms circular RNAs through backsplicing of exon 12 to either exon 10 or exon 7 (12→10; 12→7), and that these circular RNAs are translated into proteins.

Using stable cell lines overexpressing the circular tau RNAs 12→7 and 12→10, we have discovered that the tau circular RNA 12→7 is translated in a rolling circle, giving rise to multiple proteins. This circular RNA …

The Receptor Basis Of Serotonergic Modulation In An Olfactory Network, Tyler Ryan Sizemore

Graduate Theses, Dissertations, and Problem Reports

Neuromodulation is a nearly ubiquitous process that endows the nervous system with the capacity to alter neural function at every level (synaptic, circuit, network, etc.) without necessarily adding new neurons. Through the actions of neuromodulators, the existing neural circuitry can be adaptively tuned to achieve flexible network output and similarly dynamic behavioral output. However, despite their near ubiquity in all sensory modalities, the mechanisms underlying neuromodulation of sensory processing remain poorly understood. In this dissertation, I address three main questions regarding the mechanisms of one modulator (serotonin) within one sensory modality (olfaction). I begin by establishing a "functional atlas" of …

Employing High Probability Gene Choice Elements To Understand Singular Odorant Receptor Expression, Raena Mina

Dissertations, Theses, and Capstone Projects

The ability to detect odorous chemicals in the environment is the oldest of the senses necessary for survival, from escaping danger, finding mates, to locating food. It is said that humans can identify and discriminate up to a trillion different odor mixtures. For chemoreception to have such a high discriminatory power, would require a diverse population of cells dedicated for odor detection. These detector cells are the olfactory sensory neurons (OSNs), which express odorant receptors (ORs) that bind to chemical odors in the environment. In order to increase specificity and sensitivity, an essential property in olfaction is for each OSN …

Do Innexins Function In The Extreme Cold Response Of Drosophila Melanogaster, Madison A. Ward

Masters Theses, 2020-current

Nociception is an organism’s ability to detect, process and reflexively respond to potentially damaging stimuli. While the process of nociception has clear, protective advantages, inappropriate and prolonged signaling can lead to chronic pain in humans. Nociception is a vital and genetically conserved process, thus cold nociception in Drosophilaprovides a model for identifying molecular components required for nociceptor function in vertebrates. Drosophila Class III dendritic arborization (da) neurons have previously been shown to be involved in the cold nociceptive response. Due to the importance of fast response to damaging stimuli, we hypothesize that electrical synapses are involved in cold nociception. …

Tamalin/Gras-1 Connects Glutamate Receptor Activity To The Insulin/Igf Signaling Cascade To Regulate Neuroprotection In A Nematode Model Of Excitotoxicity, Ayesha Chowdhury

Dissertations, Theses, and Capstone Projects

Brain ischemia is a major cause of debilitation and death in the United States. Excitotoxicity, a condition that arises from the accumulation of glutamate (Glu) in the synapse that leads to overactivation of Glu receptors (GluRs), is the major mechanism of neuronal damage in brain ischemia / stroke. Although it is commonly acknowledged that over activation of GluRs leads to neurodegeneration, it has been recently shown that even during excitotoxicity Glu has a concurrent important role in regulating neuroprotection. GluR-activated transcription factors seem to mediate this neuroprotection, but it remains unclear which signaling cascades and transcription factors are regulated by …

Behavioural And Molecular Consequences Of Postnatal Stress In A Mouse Model Of Fetal Alcohol Spectrum Disorder, Bonnie Alberry

Electronic Thesis and Dissertation Repository

Fetal alcohol spectrum disorders (FASD) are caused by prenatal alcohol exposure (PAE) and affect 1‑5% of the North American population. Children born with FASD often face maternal separation throughout childhood. How this early life stress (ELS) affects the severity of FASD-related deficits is poorly understood. Using a mouse model, this dissertation establishes that behavioural deficits accumulate following prenatal alcohol exposure and early life stress, assessed using tests for activity, anxiety-like behaviour as well as learning and memory. Hippocampal gene expression was evaluated using RNA-seq followed by clustering of expression profiles through weighted gene co-expression network analysis (WGCNA). A set of …

Apoe As A Metabolic Regulator In Humans, Mice, And Astrocytes, Brandon C. Farmer

Theses and Dissertations--Physiology

Altered metabolic pathways appear to play central roles in the pathophysiology of late-onset Alzheimer’s disease (AD). Carrier status of the E4 allele of the APOE gene is the strongest genetic risk factor for late-onset AD, and increasing evidence suggests that E4 carriers may be at an increased risk for neurodegeneration based on inherent metabolic impairments. A new appreciation is forming for the role of APOE in cerebral metabolism, and how nutritional factors may impact this role. In chapter 1, the literature on nutritional interventions in E4 carriers aimed at mitigating disease risk is reviewed. Studies investigating the mechanism by which …

A Novel Kinesin Adapter Directly Mediates Dendritic Mrna Localization During Synapse Development, Hao Wu

Dissertations, Theses, and Capstone Projects

Cytoskeleton based active transport with motor proteins is essential for mRNA localization and local protein translation in animal cells, yet how mRNA granules interact with motor proteins remains poorly understood. Using an unbiased screen for interaction between mRNA binding proteins (RBP) and motor proteins, we identified protein interacting with APP tail 1 (PAT1) as a potential direct adapter between the β-actin mRNA Zipcode-binding protein 1 (ZBP1) and Kinesin-1 motor complex.

Mouse PAT1 is similar to the Kinesin Light Chain (KLC) in amino acid sequence and binds directly to KLC. High-resolution images from structured illumination microscopy (SIM) indicates that synaptic stimulation …

Mutations Of Fus Cause Aggregation Of Rna Binding Proteins, Disruptions In Protein Synthesis, And Dysregulation Of Nonsense Mediated Decay, Marisa Elizabeth Kamelgarn

Theses and Dissertations--Toxicology and Cancer Biology

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron death and subsequent muscle atrophy. Approximately 15% of ALS cases are inheritable, and mutations in the Fused in Sarcoma (FUS) gene contribute to approximately 5% of these cases, as well as about 2% of sporadic cases. FUS performs a diverse set of cellular functions, including being a major regulator of RNA metabolism. FUS undergoes liquid- liquid phase transition in vitro, allowing for its participation in stress granules and RNA transport granules. Phase transition also contributes to the formation of cytoplasmic inclusions found in the …

Investigating Autophagy Dysfunction Induced By A Parkinson's Disease-Causing Mutation In Vps35, Abir Ashfakur Rahman

Boise State University Theses and Dissertations

Parkinson’s Disease (PD) is an idiopathic disorder with no known cure. With number of cases steadily rising around the world, it is imperative to turn to the underlying cellular and molecular mechanisms of the disease manifestation and neurodegeneration to craft novel modes of therapy. VPS35 is one of the few genes that have identified and definitively linked to familial PD. The particular mutation that has been associated is known to cause dysfunction of a key cellular process known as autophagy. This process is primarily responsible for clearance of unwanted, damaged or misfolded proteins, among other things. Our study reveals an …

Functional And Structural Impact Of The Loss Of The Leucine-Rich Repeat Protein Lrit1 In The Mouse Retina., Catherine Ann Cobb

Electronic Theses and Dissertations

Mutations in genes encoding the leucine-rich repeat (LRR) proteins nyctalopin and LRIT3 lead to complete congenital stationary night blindness because they are critical to depolarizing bipolar cell function in the retina. LRIT3 has two closely related family members, LRIT1 and LRIT2. In silico analyses of publicly available RNA-Seq data showed that Lrit1 was highly expressed in the retina. Here I describe the expression pattern and impact of loss of LRIT1 on retinal function. To enable these studies, we used CRISPR/Cas9 technology to create an Lrit1^-/- mouse line. Retinal morphology and morphometry analyses showed no gross changes in retinal structure …

The Effects Of Increased Camp Levels On Neuronal Differentiation In Murine Embryonic Stem Cells, And The Creation Of A Crispr-Induced C.1252c>T Point Mutation In The Adcy5 Gene, Elizabeth Zepeda

Cal Poly Humboldt theses and projects

ADCY5-related dyskinesia is a rare movement disorder with early onset in childhood and adolescence. Previous studies linked this disease to various point mutations in the ADCY5 gene. Recent studies show that two of the point mutations cause an increase in cyclic adenosine monophosphate (cAMP) levels. However, it remains unknown how increased levels of cAMP result in the phenotypes associated with this disease. My study examines the effects of increased cAMP levels on neuronal differentiation of mouse embryonic stem cells (mESCs). My experiments demonstrated successful differentiation of mESCs into the dopaminergic neuronal lineage, indicated by the presence of Tuj 1 (a …

A Neuroprotective Role For Mir-1017, A Non-Canonical Mirna, Matthew De Cruz

Master's Theses

miRNAs are post-transcriptional regulators of gene expression, with numerous being involved in neurobiology. Within the human genome a quarter of the identified miRNA loci derive from a class of miRNAs termed tailed mirtrons. Despite the identification of this large population of miRNA, no functional studies have been conducted to identify their role. In this study we examined the highly expressed and deeply conserved Drosophila 3’ tail mirtron, miR-1017, as a candidate to elucidate tailed mirtron functionality. We identified acetylcholine receptor transcripts, Da5 and Da2, as bona fide targets for miR-1017. Interestingly, Da2 is also the host transcript for miR-1017. We …

Amelioration Of Prenatal Alcohol Effects By Environmental Enrichment In A Mouse Model Of Fasd, Aniruddho Chokroborty-Hoque

Electronic Thesis and Dissertation Repository

Maternal alcohol consumption during pregnancy results in a spectrum of behavioural and cognitive deficits collectively known as Fetal Alcohol Spectrum Disorders (FASD). Currently, little is know about if and how the external environment may modulate these deficits. I have used C57BL/6 mice to study this interaction between prenatal alcohol exposure and the postnatal environment. Alcohol exposure during synaptogenesis produces high levels of anxiety-like traits and decreased memory performance. Alcohol-exposed mice (and matched unexposed controls) were put in 'environmentally-enriched' conditions of voluntary exercise, physical activities and cognitive stimulation to ascertain the effects of a positive postnatal environment. The results show that …

Chaperoning Ef Hands That Shape Calcium Response: Ncald, Hpca And S100b, Jingyi Zhang

Graduate School of Biomedical Sciences Theses and Dissertations

All organisms have an internal clock with a defined period between repetitions of activities. The period for circadian clock in human is 24.5 hours, while in mouse and rat, it is 23.5 hours. However, all organisms are forced to be in synchronization with their environment. A major environmental force that resets the internal clock to 24 hours is light. This phenomenon is defined as “light entrainment” or “phase-setting”. It is unclear how this entrainment process occurs. Studies from this laboratory indicate a role for two neuronal calcium sensor proteins: Neurocalcin  (NCALD) and S100B. For these two genes, mRNA as …

Modeling 3d Retinogenesis In Mouse Embryonic Stem Cells Following Crispr-Mediated Crx Knockdown, Pooja Prasad

Dissertations, Masters Theses, Capstones, and Culminating Projects

An emerging technology known as three-dimensional (3D) tissue engineering has allowed scientists to mimic tissues found in vivo. Previous studies indicate that it is possible to differentiate dissociated mouse embryonic stem cells (mESCs) into 3D retinal tissues in vitro (Bertacchi, 2015; Eiraku, 2012). The newly differentiated retinal tissues are said to encompass all of the major components found in retinal tissues. The generation of in vitro 3D tissues holds great potential in terms of patient-specific disease modeling. Although various diseases have been well-studied in animal models, there are limitations with regards to patient-specificity. The generation of animal models to study …

Characterization Of Vesicular Monoamine Transporter 2 And Its Role In Parkinson's Disease Pathogenesis Using Drosophila, Antonio Joel Tito Jr., Sheng Zhang

Dissertations & Theses (Open Access)

Parkinson’s disease (PD) is a progressive neurodegenerative disorder caused by the selective loss of the dopaminergic neurons in the Substantia nigra pars compacta region of the brain. PD is also the most common neurodegenerative disorder and the second most common movement disorder. PD patients exhibit the cardinal symptoms, including tremor of the extremities, rigidity, slowness of movement, and postural instability, after 70-80% of DA neurons degenerate. It is, therefore, imperative to elucidate the underlying mechanisms involved in the selective degeneration of DA neurons. Although increasing numbers of PD genes have been identified, why these largely widely expressed genes induce …

Reverse Genetic Screening Of Innexin Gap Junction Proteins In Drosophila Neurons, Shannon P. Fox

Senior Honors Projects, 2010-2019

The reflexive response and perception of pain (nociception) is an evolutionarily conserved process in animals. Pain can be a major health concern and current treatments often prove insufficient, especially in regards to chronic pain. Greater understanding of the molecular processes underlying pain sensation could lead to new and more effective treatments. The aim of this study is to investigate the molecular mechanisms of cold nociception in Drosophila melanogaster. A specific subset of peripheral sensory neurons (Class III dendritic arborization (da) neurons), are implicated in Drosophila larvae’s response to noxious cold.

Previous literature has associated a family of gap junction protein, …

Hippocalcin Response To Calcium: Do Conserved Tryptophans – W30 Or W103 – Matter?, Sunkesula K. Sagar

Graduate School of Biomedical Sciences Theses and Dissertations

Changes in intracellular calcium levels play a very important role in cell signaling, in turn, affecting neuronal functions such as memory, learning and cell death. A class of proteins called Neuronal Calcium Sensor (NCS) proteins serves to modulate the functioning of the neuronal cells in response to changes in calcium levels, and prevent neuronal apoptosis. Structurally, all NCS proteins have 4 calcium-binding EF hand motifs, although EF1 does not bind to calcium in many members. All NCS proteins have an acyl modification at the N- terminus – where a myristoyl group is added post-translationally. Hippocalcin (HPCA) is an NCS protein, …

Investigation Of Sox9 Ablation On Neural Stem Cell Behaviour After Spinal Cord Injury, Stephen Mcdonald

Electronic Thesis and Dissertation Repository

After spinal cord injury neural stem cells are activated to proliferate and differentiate primarily into astrocytes, but are unable to replace lost neurons or aid in neurological recovery. Recent research shows that the transcription factor Sox9 promotes gliogenesis while inhibiting neurogenesis, and that Sox9 ablation causes improved recovery after spinal cord injury. The purpose of this study was to determine how Sox9 ablation alters neural stem cell behaviour after spinal cord injury and whether it leads to neurological improvements. We used BrdU and YFP to label and track neural stem cells and a neural stem cell-specific Sox9 knockout mouse model …

Characterizing And Treating The Neuropathology Of Tuberous Sclerosis Complex In The Mouse, Sharon W. Way

Dissertations & Theses (Open Access)

Tuberous sclerosis complex (TSC) is a multisystem, autosomal dominant disorder affecting approximately 1 in 6000 births. Developmental brain abnormalities cause substantial morbidity and mortality and often lead to neurological disease including epilepsy, cognitive disabilities, and autism. TSC is caused by inactivating mutations in either TSC1 or TSC2, whose protein products are known inhibitors of mTORC1, an important kinase regulating translation and cell growth. Nonetheless, neither the pathophysiology of the neurological manifestations of TSC nor the extent of mTORC1 involvement in the development of these lesions is known. Murine models would greatly advance the study of this debilitating disorder. This thesis …