Life Sciences Commons^™

Characterization Of The Circadian Properties Of Runt-Related Transcription Factor 2 (Runx2) And Its Role In The Suprachiasmatic Nucleus, Meghan E. Reale

Electronic Thesis and Dissertation Repository

Circadian rhythms orchestrate physiological, behavioral and cognitive processes in order to anticipate and adapt organisms to key environmental cues. These endogenously driven oscillations are generated by a network of interlocked auto-regulatory transcriptional-translational feedback loops driven forward by the Bmal1/Clock heterodimer transcription factor. Given the ubiquitous and dynamic quality of circadian rhythms, the identification of factors involved in the coordination and regulation of the endogenous oscillations is central in broadening our understanding of biological timing systems. In an examination of gene expression in the mammalian central circadian pacemaker, the hypothalamic suprachiasmatic nucleus (SCN), revealed a previously unreported rhythmic expression of runt-related …

Functional Significance Of Ilk-Elmo2 Interactions In Epidermal Keratinocytes, Ernest Ho

Electronic Thesis and Dissertation Repository

The epidermis consists of a basal layer of undifferentiated keratinocytes and multiple suprabasal layers of differentiated keratinocytes. Undifferentiated keratinocytes are adherent and highly motile, whereas differentiated keratinocytes are comparatively less motile and downregulate cell attachments to the extracellular matrix. Integrin-linked kinase (ILK) is a scaffold protein implicated in the regulation of many cellular functions in keratinocytes, including cell attachment, migration, phagocytosis, and protein trafficking. To determine the mechanisms by which ILK is involved in these processes, I sought to identify other proteins which may interact with ILK in keratinocytes. I identified Engulfment and Cell Motility 2 (ELMO2) to interact with …

Nucleoredoxin And Wnt Signaling In F9 Cells, Leanne Sandieson

Electronic Thesis and Dissertation Repository

Nucleoredoxin is a redox sensitive protein recently shown to be involved in the Wnt/β-catenin pathway through binding dishevelled. When Wnt is present, dishevelled prevents a destruction complex from degrading β-catenin. This facilitates the translocation of β-catenin into the nucleus where it binds to TCF-LEF to impart changes in gene expression. This study used mouse F9 cells as a model to examine whether or not nucleoredoxin is involved in augmenting the Wnt/β-catenin signaling required for extraembryonic endoderm differentiation. It was found that nucleoredoxin and three dishevelled isoforms were present in F9 cells. Furthermore, nucleoredoxin was found to bind to dishevelled-2, and …

Timp-2 Decreases The Invasive Potential Of Mcf-7 And Mdamb-231 Cells Independent Of Mmp Inhibition, Mario Cepeda

Electronic Thesis and Dissertation Repository

Tissue Inhibitors of Metalloproteinases (TIMPs) are the natural inhibitors of Matrix Metalloproteinases (MMPs), a family of proteins primarily responsible for Extracellular Matrix (ECM) remodeling. TIMP-2 is a special member of the TIMP family as it is both an inhibitor and promoter of MMP activity, and can also bind the cell surface and signal inside the cell to influence cell behavior. In this study, MDAMB-231 and MCF-7 breast cancer cells were treated with physiological concentration of TIMP-2, which decreased the invasive potential of both cell lines. This was independent of MMP inhibition, and instead a decrease in the expression and secretion …

Cloning And Analysis Of Reck During Early Xenopus Laevis Development, Jessica Willson

Electronic Thesis and Dissertation Repository

Extracellular matrix (ECM) remodeling is crucial for the development and maintenance of multicellular organisms. Degradation of ECM components occurs through the activity of matrix metalloproteinases (MMPs) and their inhibitors. Reversion-inducing cysteine-rich protein with Kazal motifs (RECK) gene encodes a membrane-anchored protein and plays an important role in mediating ECM remodeling by inhibiting MMPs. To date, few in vivo studies exist examining RECK during development. The present study focuses on cloning and examining the expression of RECK during early Xenopus laevis development. A mature cDNA clone of the RECK gene was generated. RT-PCR, in situ hybridization, and immunohistochemistry were used to …

Characterization Of A Tumour Suppressor Function Of Ranbpm, Elnaz Atabakhsh

Electronic Thesis and Dissertation Repository

Ran-binding protein M (RanBPM) is an evolutionarily conserved nucleocytosolic protein that has been proposed to regulate various cellular processes, including protein stability, gene expression, receptor-mediated signalling pathways, cell adhesion, development, and apoptosis. Despite the multitude of functions attributed to RanBPM however, little is known regarding the precise mechanisms by which RanBPM executes these cellular roles. In this work, we seek to address this matter by describing functions for RanBPM in the regulation of apoptotic and pro-survival signalling pathways, and in cellular transformation.

We first identify RanBPM as a pro-apoptotic protein that regulates the activation of the intrinsic apoptotic signalling pathway …

Elimination Of The Vesicular Acetylcholine Transporter In The Forebrain Causes Hyperactivity And Deficits In Spatial Memory And Long-Term Potentiation, Amanda C. Martyn, Xavier De Jaeger, Ana C. Magalhaes, Rohit Kesarwani, Daniela F. Goncalves, Sanda Raulic, Monica S. Guzman, Michael F. Jackson, Ivan Izquierdo, John F. Macdonald, Marco A. M. Prado, Vania F. Prado

Anatomy and Cell Biology Publications

Basal forebrain cholinergic neurons, which innervate the hippocampus and cortex, have been implicated in many forms of cognitive function. Immunolesion-based methods in animal models have been widely used to study the role of acetylcholine (ACh) neurotransmission in these processes, with variable results. Cholinergic neurons have been shown to release both glutamate and ACh, making it difficult to deduce the specific contribution of each neurotransmitter on cognition when neurons are eliminated. Understanding the precise roles of ACh in learning and memory is critical because drugs that preserve ACh are used as treatment for cognitive deficits. It is therefore important to define …

Har1 And Ljamp1 Dependent Regulation Of Root Architecture In Lotus Japonicus, Chong Sung Kim

Electronic Thesis and Dissertation Repository

Here, I characterize a root-branching hypermorph of Lotus japonicus, called cluster root-like1 (crl1), which originated from a har1-1 suppressor screen. I have shown that the crl1 root phenotype is determined by two independently segregating recessive mutations, har1-1 and Ljamp1-1, with corresponding HAR1 and LjAMP1 encoding an LRR‑receptor-like kinase and a predicted homologue of the Arabidopsis ALTERED MERISTEM PROGRAM 1 protein, respectively. Unlike har1-1, the Ljamp1 mutation does not affect the symbiotic properties of L. japonicus Gifu but exerts a pleiotropic effect on shoot development. Root architecture, however, is regulated by a synergistic action of HAR1 …

Phenotypic Analysis Of Schizosaccharomyces Pombe Strains Bearing Site-Directed Mutations In The Carboxy Terminal Domain Of The Largest Subunit Of Rna Polymerase Ii, Kyle S. Hoffman

Electronic Thesis and Dissertation Repository

The phosphorylation status of the largest sub-unit of RNA polymerase II (Rpb1p) is crucial to the control of transcription in eukaryotes. The domain subject to this phosphorylation is known as the carboxyl terminal domain (CTD) and consists of multiple repeats (from 20 to 52 copies depending on the species in question) of the heptad sequence Y₁S₂P₃T₄S₅P₆S_7. Interestingly, differential phosphorylation of S₂, S₅, and S₇ residues is known to play an important role in the control of pre-mRNA processing. To determine the number …

Characterization Of A Negative Regulatory Domain In Fushi Tarazu, A Pair-Rule Protein In Drosophila Melanogaster, Elyse Susanne Burlingham

Electronic Thesis and Dissertation Repository

Fushi tarazu (FTZ) is a pair-rule protein important for the development of the anterior-posterior axis during embryogenesis. Low level ectopic expression of FTZ^Δ148-206 from a Tubulin α1 promoter, but not FTZ^1-410 (full length FTZ), results in the anti-ftz phenotype in developing Drosophila melanogaster larvae, indicating that FTZ^Δ148-206 is a hyperactive FTZ protein. Through deletion analysis, using a high level ectopic expression system and assaying survivorship, I narrowed the location of the negative regulatory domain (NRD) to the 178-206 amino acid region of FTZ. Mutations that mimic both constitutive phosphorylation and dephosphorylation in the …

The Effects Of Telomerase Inhibition On Cellular Senescence In Fetal Guinea Pig Muscle Cells, Stephanie E. Hallows

Electronic Thesis and Dissertation Repository

Low birth weight infants have a higher risk of developing metabolic syndrome, including Type II Diabetes. Fetal muscle is growth restricted in low birth weight infants and is the main tissue for determining insulin resistance. Recent studies indicate premature senescence in low birth weight rodents, which could lead to adult disease. In utero environments may play a role in the development of senescence through increased reactive oxygen species (ROS). Telomerase is present at high levels during development and protects cells from cellular stress and apoptosis. We postulate that telomerase protects cells from DNA damage and premature senescence. A primary culture …

Oncolytic Virotherapy Of Ovarian Cancer, Shoudong Li, Jessica Tong, Masmudur M. Rahman, Trevor G. Shepherd, Grant Mcfadden

Anatomy and Cell Biology Publications

In the past two decades, more than 20 viruses with selective tropism for tumor cells have been developed as oncolytic viruses (OVs) for treatments of a variety of malignancies. Of these viruses, eleven have been tested in human ovarian cancer models in preclinical studies. So far, nine phase I or II clinical trials have been conducted or initiated using four different types of OVs in patients with recurrent ovarian cancers. In this article, we summarize the different OVs that are being assessed as therapeutics for ovarian cancer. We also present an overview of recent advances in identification of key genetic …

An Analysis Of The Myocardial Transcriptome In A Mouse Model Of Cardiac Dysfunction With Decreased Cholinergic Neurotransmission, Ashbeel Roy, Aline Lara, Diogo Guimaraes, Rita Pires, Eneas R. Gomes, David E. Carter, Marcus V. Gomez, Silvia Guatimosim, Vania F. Prado, Marco A. M. Prado, Robert Gros

Anatomy and Cell Biology Publications

Autonomic dysfunction is observed in many cardiovascular diseases and contributes to cardiac remodeling and heart disease. We previously reported that a decrease in the expression levels of the vesicular acetylcholine transporter (VAChT) in genetically-modified homozygous mice (VAChT KDHOM) leads to decreased cholinergic tone, autonomic imbalance and a phenotype resembling cardiac dysfunction. In order to further understand the molecular changes resulting from chronic long-term decrease in parasympathetic tone, we undertook a transcriptome-based, microarray-driven approach to analyze gene expression changes in ventricular tissue from VAChT KDHOM mice. We demonstrate that a decrease in cholinergic tone is associated with alterations in gene expression …

Uncovering Dual Roles For Perk Signaling During Experimentally Induced Pancreatitis, Elena Fazio

Electronic Thesis and Dissertation Repository

Pancreatitis is characterized by inappropriate activation of digestive enzyme

precursors, or zymogens, local and systemic inflammation, dysregulation of

cellular calcium (Ca2+), and induction of the unfolded protein response (UPR).

The UPR consists of three distinct pathways all of which are activated during

pancreatitis. However, the molecular roles of each remain unclear. The

protein kinase RNA (PKR)-like ER kinase (PERK) pathway reduces general

protein translation by phosphorylating eIF2!, and is activated within minutes

of initiating pancreatic damage. Microarray analysis carried out by our lab

revealed robust upregulation of the PERK pathways members Activating

Transcription Factor (ATF) 3 and stanniocalcin (STC) 2. …

The Embryonic Protein Nodal Supports Metastatic Phenotypes In Breast Cancer, Daniela F. Quail

Electronic Thesis and Dissertation Repository

Metastasis is the process by which tumour cells disseminate to distant organ sites. Aberrant expression of stem cell-associated proteins within tumours is associated with metastasis and poor patient prognosis. One example of a stem cell factor that is associated with cancer progression is Nodal, a member of the TGF-β superfamily. Nodal is normally limited to pluripotent stem cells during embryonic development, and to specialized dynamic adult tissue (such as the cycling endometrium), but is aberrantly re-expressed in multiple cancer types, including melanoma, glioma, prostate cancer, and pancreatic cancer. The central objective of this thesis is to determine the role of …

The Role Of Nodal In The Regulation Of Bi-Potential Trophoblast Progenitor Cells, Alia Cloutier-Bosworth

Electronic Thesis and Dissertation Repository

The human placenta develops from highly proliferative and phenotypically plastic cells called trophoblasts. Bi-potential trophoblast stem cells differentiate into the villous pathway to form the syncytiotrophoblast layer and the extravillous trophoblast (EVT). The HTR-8/SVneo cell line is widely used to study trophoblast biology. These cells variably express villous-specific or EVT-specific genes depending on conditions. Such phenotypic plasticity is indicative of a bi-potential cytotrophoblast progenitor. Preliminary work has shown that similar to progenitors in situ, a subpopulation of HTR-8/SVneo cells expresses a6b4 integrin. This a6b4^high subset exhibits enhanced clonogenicity and differentiation capacity. This cell line also expresses Nodal, a …

Placental Insufficiency Resulting In Fetal Growth Restriction Alters Synaptic Development And Neuronal Myelination In Guinea Pigs At Term, Karolina Piorkowska

Electronic Thesis and Dissertation Repository

Aberrant neuronal connectivity in utero may underlie the association between fetal growth restriction (FGR) and increased risk for later cognitive disorders and encephalopathy. This study examines changes in synaptic development and myelination focussing on the hippocampus using a guinea pig model of placental insufficiency. Placental insufficiency was induced at mid-gestation by uterine artery ligation or cauterization which produced fetuses with a range of body weight and proportion at term. Synaptic markers, synaptophysin and synaptopodin, were decreased in FGR animals suggesting fewer synapses were formed and furthermore that fewer synapses matured with symmetrical growth restriction when compared to appropriate for gestational …

Create The Scene And Watch The Show Unfold: Following Vegetative To Embryonic Developmental Transitions By Over-Expressing Lec2 In Leaves Of Arabidopsis Thaliana, Mistianne Feeney

Electronic Thesis and Dissertation Repository

During seed development, the lytic vacuole (LV) is replaced by a protein storage vacuole (PSV) which specializes in accumulating seed storage proteins (SSPs). As seed protein reserves are mobilized upon germination, the PSV is once again replaced by the LV which takes on different roles in vegetative tissues. Cellular events occurring during these developmental transitions are not well understood, particularly, the transition between vacuole types. This research investigates whether PSVs can exist in leaves. To study vacuole transitions in leaves, an Arabidopsis thaliana line over-expressing the LEAFY COTYLEDON2 (LEC2) transcription factor was used. LEC2 is a master regulator of embryogenesis …

Identification And Characterization Of The Arabidopsis Homolog Of The Yeast Trex-2 Complex, Gang Tian

Electronic Thesis and Dissertation Repository

Nuclear pore complexes (NPCs) are vital to nuclear-cytoplasmic communication in eukaryotes. The yeast Thp1-Sac3-Cdc31-Sus1 complex, also known as the TREX-2 complex, is anchored to the NPC via the nucleoporin Nup1, and is essential for mRNA export. In this study, the Arabidopsis homolog of the yeast TREX-2 complex was discovered. Physical and functional evidence support the identification of the Arabidopsis orthologs of the yeast Thp1 and Nup1. Of three Sac3 Arabidopsis homologs, two are putative TREX-2 components. Surprisingly, none are required for mRNA export as is the yeast Sac3. Physical association with TREX-2 was observed for the two Cdc31 homologs, but …

Modulation Of G Protein-Coupled Receptor Intracellular Trafficking And Signal Transduction, Jessica L. Esseltine

Electronic Thesis and Dissertation Repository

The seven transmembrane-spanning G Protein-coupled Receptor (GPCR) super family is the largest family of cell-surface receptors, comprising greater than 650 members. GPCRs represent the primary targets of most therapeutic drugs. Desensitization, endocytosis and recycling are major mechanisms of receptor regulation and intracellular trafficking of GPCRs is linked to the Rab family of small G proteins. In the present study, we examined whether multiple Rab GTPase regulate receptor trafficking through endosomal cellular compartments as a consequence of their direct association with GPCRs. We find that Rab4, Rab7 and Rab11 all bind to the last 10 amino acid residues of the angiotensin …

Mass Spectrometry-Based Proteomics Analysis Of The Matrix Microenvironment In Pluripotent Stem Cell Culture, Christopher Hughes

Electronic Thesis and Dissertation Repository

The stem cell microenvironment contains soluble factors, support cells, and components of the extracellular matrix (ECM) that combine to effect cellular behavior. Mass spectrometry based proteomics offers the opportunity to directly assay components of extracellular microenvironments, thereby providing a sensitive means for obtaining insight into the stem cell niche. In this study we present the generation and analysis of human embryonic stem cell (hESC) and human induced pluripotent stem cell (hiPSC) matrix microenvironments using an MS-based proteomics approach.

One of the primary limitations in the proteomics analysis of hESCs and hiPSCs is the reproducible generation of sufficient cell numbers amenable …

Natural Reward Experience Alters Ampa And Nmda Receptor Distribution And Function In The Nucleus Accumbens, Kyle K. Pitchers, Susanne Schmid, Andrea R. Di Sebastiano, Xu Wang, Steven R. Laviolette, Michael N. Lehman, Lique M. Coolen

Anatomy and Cell Biology Publications

Natural reward and drugs of abuse converge upon the mesolimbic system which mediates motivation and reward behaviors. Drugs induce neural adaptations in this system, including transcriptional, morphological, and synaptic changes, which contribute to the development and expression of drug-related memories and addiction. Previously, it has been reported that sexual experience in male rats, a natural reward behavior, induces similar neuroplasticity in the mesolimbic system and affects natural reward and drug-related behavior. The current study determined whether sexual experience causes long-lasting changes in mating, or ionotropic glutamate receptor trafficking or function in the nucleus accumbens (NAc), following 3 different reward abstinence …

The Role Of Pex11-Beta In Peroxisome Biogenesis, Intracellular Relationship To Reactive Oxygen Species Levels And Redox-Sensitive Cell Signaling, Mark A. Fox

Electronic Thesis and Dissertation Repository

Peroxisomes are organelles whose roles in fatty acid metabolism and reactive oxygen species (ROS) elimination have contributed much attention in understanding their origin and biogenesis. Many studies have shown that de novo peroxisome biogenesis is an important regulatory process, while yeast studies suggest that total peroxisome numbers are in part regulated by proteins such as Pex11, which can facilitate the division of existing peroxisomes. Although de novo biogenesis and divisions are likely important mechanisms to peroxisome functioning, the regulation of peroxisome numbers during embryonic development is poorly understood. Peroxisome number and function are particularly crucial in oviparous animals such as …

Molecular Mechanisms Of Cell Migration Inhibition By Synthetic Triterpenoids, Ciric Chi Wing To

Electronic Thesis and Dissertation Repository

Cell migration is an important mediator of cancer metastasis and invasion, which is responsible for 90% of cancer-related premature deaths in Canada. Synthetic triterpenoids are a class of promising anti-cancer compounds that have shown considerable efficacy in targeting various cellular functions including apoptosis, growth, inflammation and cytoprotection in both cell culture and animal tumor models. However, their effect on cell migration, an important event in metastasis, remains poorly understood. This thesis focuses on deciphering the molecular mechanisms whereby the synthetic triterpenoids affect cell migration. I observed that the imidazolide and methyl ester derivatives of the synthetic triterpenoid, 2-cyano-3,12-dioxooleana-1,9-dien-28-oic aic acid …

The Developmental And Adaptive Role Of Mitogen Activated Protein Kinase Pathways During Preimplantation Development, Christine E. Bell

Electronic Thesis and Dissertation Repository

The preimplantation period of development represents the highest interval of embryonic loss throughout pregnancy. It is therefore imperative that we elucidate the mechanisms involved in regulating preimplantation embryonic responses to stress and that govern development. The MAPK pathways are involved in both responding to environmental stress and regulation of development throughout embryogenesis, and are therefore good candidates to study the mechanisms involved in preimplantation embryonic adaptation to stress and development. The preimplantation embryo culminates in the development of a fluid filled structure called the blastocyst. It is at this stage the first differentiation events occur and the trophectoderm (TE), which …

Perceptual Enhancement Of Arteriovenous Malformation In Mri Angiography Displays, Abhari Kamyar, John S. H. Baxter, Roy Eagleson, Terry Peters, Sandrine De Ribaupierre

Anatomy and Cell Biology Publications

The importance of presenting medical images in an intuitive and usable manner during a procedure is essential. However, most medical visualization interfaces, particularly those designed for minimally-invasive surgery, suffer from a number of issues as a consequence of disregarding the human perceptual, cognitive, and motor system's limitations. This matter is even more prominent when human visual system is overlooked during the design cycle. One example is the visualization of the neuro-vascular structures in MR angiography (MRA) images. This study investigates perceptual performance in the usability of a display to visualize blood vessels in MRA volumes using a contour enhancement technique. …