Molecular Biology Commons^™

Molecular Mechanisms Regulating Neonatal Oocyte Survival And Primordial Follicle Formation In The Mouse Ovary, Robin L. Jones

Biology - Dissertations

In mammals, formation of the primordial follicle is a complex process involving the breakdown of germ cell cysts, where oocytes must separate from each other and subsequently become surrounded by somatic cells. As cysts separate, a large number of germ cells are lost by apoptosis, however the mechanisms by which cyst breakdown and germ cell death occur are not well understood. We first hypothesized that two anti-apoptotic regulators from the BCL2 family of proteins, BCL2 and MCL1, may be responsible for regulating neonatal oocyte survival. To elucidate the effects of BCL2 in the neonatal ovary, we examined ovaries of both …

Identification And Functional Characterization Of The Zebrafish Gene Quetschkommode (Que), Timo Friedrich

Open Access Dissertations

Locomotion in vertebrates depends on proper formation and maintenance of neuronal networks in the hind-brain and spinal cord. Malformation or loss of factors required for proper maintenance of these networks can lead to severe neurodegenerative diseases limiting or preventing locomotion. A powerful tool to investigate the genetic and cellular requirements for development and/or maintenance of these networks is a collection of zebrafish mutants with defects in motility. The zebrafish mutant quetschkommode (que) harbors a previously unknown gene defect leading to abnormal locomotor behavior. Here I show that the que mutants display a seizure-like behavior starting around four days post fertilization …

An Analysis Of The Redox Properties And Stability Of Chlamydomonas Reinhardtii Cytochrome F, Cytochrome C6, And Mutants Thereof, Nicole Lynn Vanderbush

Graduate Theses and Dissertations

This body of work presents mutagenesis studies conducted on two c-type cytochromes from Chlamydomonas reinhardtii. Cytochrome f, a unique c-type cytochrome, is investigated in regards to its redox potential, the dependence of the redox potential, and the thermal stability of the protein. The mutations made were Y1F, Y9F, Y160F, Y160L, R156L, and R156K. The residues that were mutated surround the heme. It was found that, relative to the wild-type, only the Y160L and R156 mutants showed any difference in midpoint potential at pH 7. Wild-type and mutants both had a midpoint potential that was dependent upon pH indicating that none …

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 …

Elucidating The Effect Of Silver On Ethylene Signaling In Arabidopsis Thaliana, Brittany Kathleen Mcdaniel

Masters Theses

Ethylene, a gaseous plant hormone, is involved in numerous plant developmental processes such as seed germination, senescence, and fruit ripening. In Arabidopsis thaliana, ethylene is perceived by a family of five membrane-bound receptors, which upon binding ethylene trigger downstream effects. At the receptor level, it is known that the coordination of a copper ion is necessary for ethylene to bind, resulting in a conformational change of the receptor and the initiation of the ethylene signal transduction pathway. Interestingly, silver ions are also able to support binding of ethylene but ethylene responses are blocked in the presence of silver. When …

Genome-Wide Identification Of Conditionally Essential Genes In Salmonella Typhimurium Using Tn-Seq Method, Anita Khatiwara

Graduate Theses and Dissertations

ABSTRACT

As more whole genome sequences become available, there is an increasing need for high-throughput methods that link genes to phenotypes and facilitate discovery of new gene functions. The objective of this study was to develop a high-throughput method to study gene functions in bacteria and use this method to study gene functions of S. enterica serotype Typhimurium (S. Typhimurium) under various environmental conditions encountered during its life cycle. Chapter I of this dissertation reviews the history and evolution of functional genomics in bacteria with focus on Salmonella, along with the recent techniques available. Chapter II, deals with the development …

Regulation Of Protein Degradation In The Heart By Amp-Activated Protein Kinase, Kedryn K. Baskin, Kedryn K. Baskin

Dissertations & Theses (Open Access)

The degradation of proteins by the ubiquitin proteasome system is essential for cellular homeostasis in the heart. An important regulator of metabolic homeostasis is AMP-activated protein kinase (AMPK). During nutrient deprivation, AMPK is activated and intracellular proteolysis is enhanced through the ubiquitin proteasome system (UPS). Whether AMPK plays a role in protein degradation through the UPS in the heart is not known. Here I present data in support of the hypothesis that AMPK transcriptionally regulates key players in the UPS, which, under extreme conditions can be detrimental to the heart. The ubiquitin ligases MAFbx /Atrogin-1 and MuRF1, key regulators of …

Syntaxin 6- And Microtubule- Mediated Intracellular Trafficking Contributes To Golgi And Nuclear Translocation Of Egfr, Yi Du

Dissertations & Theses (Open Access)

Receptor-mediated endocytosis is well known for its degradation and recycling trafficking. Recent evidence shows that these cell surface receptors translocate from cell surface to different cellular compartments, including the Golgi, mitochondria, endoplasmic reticulum (ER), and the nucleus to regulate physiological and pathological functions. Although some trafficking mechanisms have been resolved, the mechanism of intracellular trafficking from cell surface to the Golgi is not yet completed understood. Here we report a mechanism of Golgi translocation of EGFR in which EGF-induced EGFR travels to the Golgi via microtubule (MT)-dependent movement by interacting with dynein and fuses with the Golgi through syntaxin 6 …

Regulation Of Protein Degradation In The Heart By Amp-Activated Protein Kinase, Kedryn K. Baskin

Dissertations & Theses (Open Access)

The degradation of proteins by the ubiquitin proteasome system is essential for cellular homeostasis in the heart. An important regulator of metabolic homeostasis is AMP-activated protein kinase (AMPK). During nutrient deprivation, AMPK is activated and intracellular proteolysis is enhanced through the ubiquitin proteasome system (UPS). Whether AMPK plays a role in protein degradation through the UPS in the heart is not known. Here I present data in support of the hypothesis that AMPK transcriptionally regulates key players in the UPS, which, under extreme conditions can be detrimental to the heart. The ubiquitin ligases MAFbx /Atrogin-1 and MuRF1, key regulators of …

The Dietary Isoprenoid Perillyl Alcohol Inhibits Telomerase Activity In Prostate Cancer Cells, Tabetha Sundin

Theses and Dissertations in Biomedical Sciences

This is the first evidence that a plant-derived compound–perillyl alcohol regulates telomerase activity via the mammalian target of rapamycin (mTOR) pathway in prostate cancer cells. Telomerase–the enzyme responsible for immortalizing cells through telomeric repeats addition–is de-repressed early in an aspiring cancer cell. We hypothesized that perillyl alcohol regulates hTERT (human telomerase reverse transcriptase) at the translational and post-translational levels via its effects on the mTOR pathway. A rapid suppression of telomerase activity was detected in prostate cancer cell lines (PC-3 and DU145) in response to biologically-relevant concentrations and short incubations of perillyl alcohol or the mTOR inhibitor—rapamycin.

Western blot analysis …

The Role Of Tumor Suppressors, Ship And Rb, In Immune Suppressive Cells, Michelle Marie Collazo Ruiz

USF Tampa Graduate Theses and Dissertations

Regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSC) have been extensively studied in the past 30-40 years. Their potent suppressive capacity shown in several pathological and clinical settings, such as cancer and transplantation, has made it evident that better understanding their development and function is critical.

Specifically, Tregs play a pivotal role in preventing autoimmunity, graft-versus-host disease (GvHD), and organ graft rejection. We previously demonstrated that germline or induced SH2 domain-containing inositol 5-phosphatase (SHIP) deficiency in the host abrogates GvHD. Here we show that SHIP-deficiency promotes an increase of FoxP3+ cells in both the CD4+CD25+ and the CD4+CD25- T …

Identifying Sm22 As A Key Player In Arterial Diseases, Jianbin Shen

Wayne State University Dissertations

Background : Expression of vascular smooth muscle cell (VSMC) cytoskeleton markers including SM22 is down-regulated in arterial diseases including atherosclerosis where inflammation and osteochondrogenesis are present. However, the role of this downregulation in arterial pathogenesis is unknown. Hypothesis : Downregulation of SM22 may actively contribute to arterial pathogenesis. Methods : Five Sm22 knockout (Sm22^-/-) mice and their wild type littermates were subjected to carotid artery denudation, an artery injury model. Analyses were conducted on carotid arteries 2 weeks after injury. Primary VSMCs were isolated from mouse aortas and investigated individually at passage 2 to 4. Sm22 knockdown was …

Identification Of Cellular Functions Of Cardiolipin As Physiological Modifiers Of Barth Syndrome, Amit Shridhar Joshi

Wayne State University Dissertations

Cardiolipin (CL) is an anionic phospholipid synthesized in the mitochondrial inner membrane. Perturbation of CL metabolism leads to Barth syndrome (BTHS), a life threatening genetic disorder. I utilized genetic, biochemical and cell biological approaches in yeast to elucidate the cellular functions of CL. Understanding the functions of CL is expected to shed light on the pathology and possible treatments for BTHS.

BTHS is caused by mutations in TAZ1, which encodes a CL remodeling enzyme called tafazzin. BTHS patients exhibit a wide range of clinical presentations, indicating that physiological modifiers influence the BTHS phenotype. A targeted synthetic lethality screen was performed …

Hdm2 Small-Molecule Inhibitors For Therapeutic Intervention In B-Cell Lymphoma, Angela Sosin

Wayne State University Dissertations

Lymphomas frequently retain wild-type (wt) p53 function but overexpress HDM2, compromising p53 activity. Therefore, lymphoma is a suitable model for studying therapeutic value of disrupting HDM2-p53 association by small-molecule inhibitors (SMIs). HDM2 SMIs have been developed and are currently under various stages of preclinical and clinical investigation. This study examined various molecular mechanisms associated and biological effects of two different classes of HDM2 SMIs: the spiro-oxindoles (MI-219) and cis-imidazoline (Nutlin-3) in lymphoma cell lines and patient-derived B-lymphoma cells. Surprisingly, results revealed significant quantitative and qualitative differences between these two agents. At the molecular level, effect of Nutlin-3 was generally more …

A Proposal To Test The Effects Of Factor Ecat1 On Pluripotency, From Reprogramming To Differentiation Of Human Somatic Cells, Vritti R. Goel

CMC Senior Theses

The field of stem cell research has been growing more because of the interest in using stem cells to cure diseases and heal injuries. Human embryonic stem cells, because of the controversy surrounding them—and subsequently the difficulties in acquiring samples of the existing aging cell lines—can only be used in limited capacities. While the development of induced pluripotent stem cells in the last decade has allowed the field to progress closer to medical treatments, the low efficiency of reprogramming a somatic cell to a pluripotent state, and the vast molecular and genomic differences between human embryonic stem cells and human …