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Optimizing Crispr/Cas9 For Gene Silencing Of Sod1 In Mouse Models Of Als, Zachary C. Kennedy Aug 2019

Optimizing Crispr/Cas9 For Gene Silencing Of Sod1 In Mouse Models Of Als, Zachary C. Kennedy

GSBS Dissertations and Theses

Mutations in the SOD1 gene are the best characterized genetic cause of amyotrophic lateral sclerosis (ALS) and account for ~20% of inherited cases and 1-3% of sporadic cases. The gene-editing tool Cas9 can silence mutant genes that cause disease, but effective delivery of CRISPR-Cas9 to the central nervous system (CNS) remains challenging. Here, I developed strategies using canonical Streptococcus pyogenes Cas9 to silence SOD1. In the first strategy, I demonstrate effectiveness of systemic delivery of guide RNA targeting SOD1 to the CNS in a transgenic mouse model expressing human mutant SOD1 and Cas9. Silencing was observed in both the brain ...


Engineered Exosomes For Delivery Of Therapeutic Sirnas To Neurons, Reka A. Haraszti May 2018

Engineered Exosomes For Delivery Of Therapeutic Sirnas To Neurons, Reka A. Haraszti

GSBS Dissertations and Theses

Extracellular vesicles (EVs), exosomes and microvesicles, transfer endogenous RNAs between neurons over short and long distances. We have explored EVs for siRNA delivery to brain. (1) We optimized siRNA chemical modifications and siRNA conjugation to lipids for EV-mediated delivery. (2) We developed a GMP-compatible, scalable method to manufacture active EVs in bulk. (3) We characterized lipid and protein content of EVs in detail. (4) We established how protein and lipid composition relates to siRNA delivering activity of EVs, and we reverse engineered natural exosomes (small EVs) into artificial exosomes based on these data.

We established that cholesterol-conjugated siRNAs passively associate ...


Identification Of Factors Involved In 18s Nonfunctional Ribosomal Rna Decay And A Method For Detecting 8-Oxoguanosine By Rna-Seq, Kelly A. Limoncelli Dec 2017

Identification Of Factors Involved In 18s Nonfunctional Ribosomal Rna Decay And A Method For Detecting 8-Oxoguanosine By Rna-Seq, Kelly A. Limoncelli

GSBS Dissertations and Theses

The translation of mRNA into functional proteins is essential for all life. In eukaryotes, aberrant RNAs containing sequence features that stall or severely slow down ribosomes are subject to translation-dependent quality control. Targets include mRNAs encoding a strong secondary structure (No-Go Decay; NGD) or stretches of positively-charged amino acids (Peptide-dependent Translation Arrest/Ribosome Quality Control; PDTA/RQC), mRNAs lacking an in-frame stop codon (Non-Stop Decay; NSD), or defective 18S rRNAs (18S Nonfunctional rRNA Decay; 18S NRD). Previous work from our lab showed that the S. cerevisiae NGD factors DOM34 and HBS1, and PDTA/RQC factor ASC1, all participate in the ...


The Mechanistic Role And Therapeutic Potential Of Microrna-122 In Alcoholic Liver Disease: A Dissertation, Abhishek Satishchandran Apr 2016

The Mechanistic Role And Therapeutic Potential Of Microrna-122 In Alcoholic Liver Disease: A Dissertation, Abhishek Satishchandran

GSBS Dissertations and Theses

Chronic alcohol use results in accelerated liver injury, leading to alcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. However, due to the complex nature of this disease process, a central, druggable mechanism has remained elusive. microRNAs are potent post-transcriptional regulators of gene expression. A single miRNA has the ability to regulate hundreds of pathways simultaneously, defining cellular fate and function. microRNA-122 (miR-122), the most abundant miRNA in hepatocytes, has a demonstrated role as an tumor suppressor, regulator of hepatocyte metabolism, and hepatic differentiation.

In this dissertation I demonstrate the role of miR-122 on alcoholic liver disease (ALD) pathogenesis over four parts. In ...


Yeast Upf1 Associates With Ribosomestranslating Mrna Coding Sequences Upstream Of Normal Termination Codons: A Dissertation, Ei Ei Min Apr 2015

Yeast Upf1 Associates With Ribosomestranslating Mrna Coding Sequences Upstream Of Normal Termination Codons: A Dissertation, Ei Ei Min

GSBS Dissertations and Theses

Nonsense-mediated mRNA decay (NMD) specifically targets mRNAs with premature translation termination codons for rapid degradation. NMD is a highly conserved translation-dependent mRNA decay pathway, and its core Upf factors are thought to be recruited to prematurely terminating mRNP complexes, possibly through the release factors that orchestrate translation termination. Upf1 is the central regulator of NMD and recent studies have challenged the notion that this protein is specifically targeted to aberrant, nonsense-containing mRNAs. Rather, it has been proposed that Upf1 binds to most mRNAs in a translation-independent manner. In this thesis, I investigated the nature of Upf1 association with its substrates ...


Dissecting The Role Of A Lncrna And Involvement Of Plasmodium Infections In The Innate Immune Response: A Dissertation, Jennie Chan Apr 2015

Dissecting The Role Of A Lncrna And Involvement Of Plasmodium Infections In The Innate Immune Response: A Dissertation, Jennie Chan

GSBS Dissertations and Theses

The innate immune system is a multicomponent response governed by intricate mechanisms of induction, regulation and resolution to elicit antimicrobial defenses. In recent years, the complexity of eukaryotic transcriptomes has become the subject of intense scrutiny and curiosity. It has been established, that RNA polymerase II (RNAPII) transcribes hundreds to thousands of long noncoding RNAs (lncRNAs), often in a stimulus and cell-type specific manner. However, the functional significance of these transcripts has been particularly controversial. While the number of identified lncRNAs is growing, our understanding of how lncRNAs themselves regulate other genes is quite limited. In chapter 2, a novel ...


Subtle Controllers: Micrornas Drive Pancreatic Tumorigenesis And Progression: A Dissertation, Brian J. Quattrochi Apr 2015

Subtle Controllers: Micrornas Drive Pancreatic Tumorigenesis And Progression: A Dissertation, Brian J. Quattrochi

GSBS Dissertations and Theses

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal malignancies in the United States, with an average five-year survival rate of just 6.7%. One unifying aspect of PDAC is mutational activation of the KRAS oncogene, which occurs in over 90% of PDAC. Therefore, inhibiting KRAS function is likely an effective therapeutic strategy for this disease, and current research in our lab and others is focused on identifying downstream effectors of KRAS signaling that may be therapeutic targets. miRNAs are powerful regulators of gene expression that can behave as oncogenes or tumor suppressors. Dysregulation of miRNA expression is commonly observed ...


Hepatitis C Virus Non-Structural Protein 3/4a: A Tale Of Two Domains: A Dissertation, Cihan Aydin Aug 2012

Hepatitis C Virus Non-Structural Protein 3/4a: A Tale Of Two Domains: A Dissertation, Cihan Aydin

GSBS Dissertations and Theses

Two decades after the discovery of the Hepatitis C Virus (HCV), Hepatitis C infection still persists to be a global health problem. With the recent approval of the first set of directly acting antivirals (DAAs), the rate of sustained viral response for HCV-infected patients increased significantly. However, a complete cure has not been found yet. Drug development efforts primarily target NS3/4A protease, bifunctional serine protease-RNA helicase of HCV. HCV NS3/4A is critical in viral function; protease domain processes the viral polyprotein and helicase domain aids replication of HCV genome by unwinding double stranded RNA transcripts produced by NS5B ...


Sequence And Target Specificity Of The C. Elegans Cell Fate Specification Factor Pos-1: A Dissertation, Brian M. Farley Aug 2012

Sequence And Target Specificity Of The C. Elegans Cell Fate Specification Factor Pos-1: A Dissertation, Brian M. Farley

GSBS Dissertations and Theses

In most metazoans, early embryogenesis is controlled by the translational regulation of maternally supplied mRNA. Sequence-specific RNA-binding proteins play an important role in regulating early embryogenesis, yet their specificities and regulatory targets are largely unknown. To understand how these RNA-binding proteins select their targets, my research focused on the C. elegans CCCH-type tandem zinc finger protein POS-1. Embryos lacking maternally supplied POS-1 die prior to gastrulation, and exhibit defects in the specification of pharyngeal, intestinal, and germline precursor cells. To identify the regulatory targets that contribute to the POS-1 mutant phenotype, we set out to determine the sequence specificity of ...


Protein Ligand Interactions Probed By Nmr: A Dissertation, Jennifer M. Laine Jul 2012

Protein Ligand Interactions Probed By Nmr: A Dissertation, Jennifer M. Laine

GSBS Dissertations and Theses

Molecular recognition, defined as the specific interactions between two or more molecules, is at the center of many biological processes including catalysis, signal transduction, gene regulation and allostery. Allosteric regulation is the modification of function caused by an intermolecular interaction. Allosteric proteins modify their activity in response to a biological signal that is often transmitted through the interaction with a small effector molecule. Therefore, determination of the origins of intermolecular interactions involved in molecular recognition and allostery are essential for understanding biological processes. Classically, molecular recognition and allosteric regulation have been associated to structural changes of the system. NMR spectroscopic ...


Microrna Markers Of Acetaminophen Toxicity: A Master's Thesis, Jeanine Ward Jul 2012

Microrna Markers Of Acetaminophen Toxicity: A Master's Thesis, Jeanine Ward

GSBS Dissertations and Theses

Background
To investigate plasma microRNA (miRNA) profiles indicative of hepatotoxicity in the setting of lethal acetaminophen (APAP) toxicity in mice.

Methods
Using plasma from APAP poisoned mice, either lethally (500 mg/kg) or sublethally (150 mg/kg) dosed, we screened commercially available murine microRNA libraries (SABiosciences, Qiagen Sciences, MD) to evaluate for unique miRNA profiles between these two dosing parameters.

Results
We distinguished numerous, unique plasma miRNAs both up- and down-regulated in lethally compared to sublethally dosed mice. Of note, many of the greatest up- and down-regulated miRNAs, included, but were not limited to, 574-5p, 466g, 466f-3p, 375, 29c, and ...


Gene Expression And Profiling Of Human Islet Cell Subtypes: A Master’S Thesis, David M. Blodgett Jul 2012

Gene Expression And Profiling Of Human Islet Cell Subtypes: A Master’S Thesis, David M. Blodgett

GSBS Dissertations and Theses

Background: The endocrine pancreas contains multiple cell types co-localized into clusters called the Islets of Langerhans. The predominant cell types include alpha and beta cells, which produce glucagon and insulin, respectively. The regulated release of these hormones maintains whole body glucose homeostasis, essential for normal metabolism and to prevent diabetes and complications from the disease. Given the heterogeneous nature of islet composition and absence of unique surface markers, many previous studies have focused on the whole islet. Sorting islet cells by intracellular hormone expression overcomes this limitation and provides pure populations of individual islet cell subsets, specifically alpha and beta ...


Rna-Sensing Pattern Recognition Receptors And Their Effects On T-Cell Immune Responses: A Dissertation, Rachel F. Madera Jul 2012

Rna-Sensing Pattern Recognition Receptors And Their Effects On T-Cell Immune Responses: A Dissertation, Rachel F. Madera

GSBS Dissertations and Theses

Virus infection is sensed by the innate immune system through germline encoded pattern recognition receptors (PRRs). Toll-like receptors (TLRs), retinoic acid-inducible gene-I-like receptors (RLRs) and nucleotide-binding oligomerization domain-like receptors (NLRs) serve as PRRs that recognize different viral components. Microbial nucleic acids such as Ribonucleic acid (RNA) are important virus-derived pathogen-associated molecular patterns (PAMPs) to be recognized by PRRs. Virus recognition may occur at multiple stages of the viral life cycle. Replication intermediates such as single-stranded RNA (ssRNA) and double-stranded RNA (dsRNA) are detected by the RNA-sensing PRRs that initiate innate and adaptive immune responses. Triggering of the innate immune system ...


Understanding Small Rna Formation In Drosophila Melanogaster: A Dissertation, Elif Sarinay Cenik Jul 2012

Understanding Small Rna Formation In Drosophila Melanogaster: A Dissertation, Elif Sarinay Cenik

GSBS Dissertations and Theses

Drosophila Dicer-2 generates small interfering RNAs (siRNAs) from long double-stranded RNA (dsRNA), whereas Dicer-1 produces microRNAs from premicroRNA. My thesis focuses on the functional characteristics of two Drosophila Dicers that makes them specific for their biological substrates. We found that RNA binding protein partners of Dicers and two small molecules, ATP and phosphate are key in regulating Drosophila Dicers’ specificity. Without any additional factor, recombinant Dicer-2 cleaves pre-miRNA, but its product is shorter than the authentic miRNA. However, the protein R2D2 and inorganic phosphate block pre-miRNA processing by Dicer-2. In contrast, Dicer-1 is inherently capable of processing the substrates of ...


Therapeutic Silencing Of Mutant Huntingtin By Targeting Single Nucleotide Polymorphisms: A Dissertation, Edith L. Pfister Jul 2012

Therapeutic Silencing Of Mutant Huntingtin By Targeting Single Nucleotide Polymorphisms: A Dissertation, Edith L. Pfister

GSBS Dissertations and Theses

Huntington’s disease (HD) is an autosomal dominant, progressive neurodegenerative disorder. Invariably fatal, HD is caused by expansion of the CAG repeat region in exon 1 of the Huntingtin gene which creates a toxic protein with an extended polyglutamine tract 1. Silencing mutant Huntingtin messenger RNA (mRNA) is a promising therapeutic approach 2-6. The ideal silencing strategy would reduce mutant Huntingtin while leaving the wild-type mRNA intact. Unfortunately, targeting the disease causing CAG repeat expansion is difficult and risks targeting other CAG repeat containing genes.

We examined an alternative strategy, targeting single nucleotide polymorphisms (SNPs) in the Huntingtin mRNA. The ...


Transposition Driven Genomic Heterogeneity In The Drosophila Brain: A Dissertation, Paola N. Perrat Jun 2012

Transposition Driven Genomic Heterogeneity In The Drosophila Brain: A Dissertation, Paola N. Perrat

GSBS Dissertations and Theses

In the Drosophila brain, memories are processed and stored in two mirrorsymmetrical structures composed of approximately 5,000 neurons called Mushroom Bodies (MB). Depending on their axonal extensions, neurons in the MB can be further classified into three different subgroups: αβ, α’β’ and γ. In addition to the morphological differences between these groups of neurons, there is evidence of functional differences too. For example, it has been previously shown that while neurotransmission from α’β’ neurons is required for consolidation of olfactory memory, output from αβ neurons is required for its later retrieval. To gain insight into the functional ...


Genetic Approaches To Study Transcriptional Activation And Tumor Suppression: A Dissertation, Ling Lin May 2012

Genetic Approaches To Study Transcriptional Activation And Tumor Suppression: A Dissertation, Ling Lin

GSBS Dissertations and Theses

The development of methods and techniques is the driving force of scientific research. In this work, we described two large-scale screens in studying transcriptional activation and tumor suppression.

In Part I, we studied transcriptional activation mechanisms by deriving and characterizing activation defective mutants. Promoter-specific transcriptional activators stimulate transcription through direct interactions with one or more components of the transcription machinery, termed the “target.” The identification of direct in vivo targets of activators has been a major challenge. We perform a large-scale genetic screen to derive and characterize tra1 alleles that are selectively defective for interaction with Gal4 in vivo. Utilizing ...


Molecular Mechanisms Of Endocytosis: Trafficking And Functional Requirements For The Transferrin Receptor, Small Interfering Rnas And Dopamine Transporter: A Dissertation, Deanna M. Navaroli Apr 2012

Molecular Mechanisms Of Endocytosis: Trafficking And Functional Requirements For The Transferrin Receptor, Small Interfering Rnas And Dopamine Transporter: A Dissertation, Deanna M. Navaroli

GSBS Dissertations and Theses

Endocytosis is an essential function of eukaryotic cells, providing crucial nutrients and playing key roles in interactions of the plasma membrane with the environment. The classical view of the endocytic pathway, where vesicles from the plasma membrane fuse with a homogenous population of early endosomes from which cargo is sorted, has recently been challenged by the finding of multiple subpopulations of endosomes. These subpopulations vary in their content of phosphatidylinositol 3- phosphate (PI3P) and Rab binding proteins. The role of these endosomal subpopulations is unclear, as is the role of multiple PI3P effectors, which are ubiquitously expressed and highly conserved ...


Analysis Of Integrin Α6Β4 Function In Breast Carcinoma: A Dissertation, Kristin D. Gerson Apr 2012

Analysis Of Integrin Α6Β4 Function In Breast Carcinoma: A Dissertation, Kristin D. Gerson

GSBS Dissertations and Theses

The development and survival of multicellular organisms depends upon the ability of cells to move. Embryogenesis, immune surveillance, wound healing, and metastatic disease are all processes that necessitate effective cellular locomotion. Central to the process of cell motility is the family of integrins, transmembrane cell surface receptors that mediate stable adhesions between cells and their extracellular environment. Many human diseases are associated with aberrant integrin function. Carcinoma cells in particular can hijack integrins, harnessing their mechanical and signaling potential to propagate cell invasion and metastatic disease, one example being integrin α6β4. This integrin, often referred to simply as β4, is ...


Dissecting Somatic Cell Reprogramming By Micrornas And Small Molecules: A Dissertation, Zhonghan Li Mar 2012

Dissecting Somatic Cell Reprogramming By Micrornas And Small Molecules: A Dissertation, Zhonghan Li

GSBS Dissertations and Theses

Somatic cells could be reprogrammed into an ES-like state called induced pluripotent stem cells (iPSCs) by expression of four transcriptional factors: Oct4, Sox2, Klf4 and cMyc. iPSCs have full potentials to generate cells of all lineages and have become a valuable tool to understand human development and disease pathogenesis. However, reprogramming process suffers from extremely low efficiency and the molecular mechanism remains poorly understood.

This dissertation is focused on studying the role of small non-coding RNAs (microRNAs) and kinases during the reprogramming process in order to understand how it is regulated and why only a small percentage of cells could ...


Characterization Of New Factors In The 18s Nonfunctional Ribosomal Rna Decay Pathway In S. Cerevisiae: A Dissertation, Christopher N. Merrikh Mar 2012

Characterization Of New Factors In The 18s Nonfunctional Ribosomal Rna Decay Pathway In S. Cerevisiae: A Dissertation, Christopher N. Merrikh

GSBS Dissertations and Theses

The molecular biology revolution of the 1960s has given rise to an enormous body of literature describing, in great detail, the inner workings of the cell. Over the course of the past 50 years, and countless hours at the bench, biologists have used the implications of basic research to produce vaccines, antibiotics, and other therapies that have improved both the quality and duration of our lives. Despite these incredible advances, basic questions remain unanswered. In even the simplest model organism, hundreds of essential genes have never been studied. Moreover, the central dogma of molecular biology—DNA to RNA to Protein ...


Studies On The Regulation Of Cytoplasmic Polyadenylation Element-Binding Protein: A Dissertation, Chien-Ling Lin Jan 2012

Studies On The Regulation Of Cytoplasmic Polyadenylation Element-Binding Protein: A Dissertation, Chien-Ling Lin

GSBS Dissertations and Theses

Post-transcriptional regulation of gene expression sits at the core of proteomic complexity; trans-acting factors that regulate RNA localization and translation capacity are thus indispensible. In this thesis, I present studies of the cytoplasmic polyadenylation element binding protein (CPEB), a sequence specific RNA-binding protein important for cell cycle progression and neural synaptic plasticity. I focus on CPEB because the activity of RNA-binding proteins affects the destiny of their mRNA substrates. As presented in Chapter II, CPEB, though mostly cytoplasmic at steady state, shuttles between the nucleus and the cytoplasm. Surprisingly, the RNA recognition motifs are essential for the nuclear localization ...


Cellular And Molecular Mechanisms Driving Glial Engulfment Of Degenerating Axons: A Dissertation, Johnna E. Doherty Nov 2011

Cellular And Molecular Mechanisms Driving Glial Engulfment Of Degenerating Axons: A Dissertation, Johnna E. Doherty

GSBS Dissertations and Theses

The nervous system is made up of two major cell types, neurons and glia. The major distinguishing feature between neuronal cells and glial cells is that neurons are capable of transmitting action potentials while glial cells are electrically incompetent. For over a century glial cells were neglected and it was thought they existed merely to provide trophic and structural support to neurons. However, in the past few decades it has become increasingly clear that glial cell functions underlie almost all aspects of nervous system development, maintenance, and health. During development, glia act as permissive substrates for axons, provide guidance cues ...


Cooperativity In Mammalian Rna Silencing: A Dissertation, Jennifer A. Broderick Jul 2011

Cooperativity In Mammalian Rna Silencing: A Dissertation, Jennifer A. Broderick

GSBS Dissertations and Theses

Argonaute proteins are the core component of an RNA silencing complex. The human genome encodes four Argonaute paralogs –Ago1, Ago2, Ago3 and Ago4– proteins that are guided to target mRNAs by microRNAs. More than 500 miRNAs are conserved between mammals, and each microRNA can repress hundreds of genes, regulating almost every cellular process. We still do not fully understand the molecular mechanisms by which miRNAs regulate gene expression. Although we understand many aspects of microRNA biogenesis and formation of the RNA-induced silencing complex, much less is known about the subsequent steps leading to target mRNA regulation.

Mammalian microRNAs rarely have ...


Nucleic Acid Sensing By The Immune System: Roles For The Receptor For Advanced Glycation End Products (Rage) And Intracellular Receptor Proteins: A Dissertation, Cherilyn M. Sirois Jul 2011

Nucleic Acid Sensing By The Immune System: Roles For The Receptor For Advanced Glycation End Products (Rage) And Intracellular Receptor Proteins: A Dissertation, Cherilyn M. Sirois

GSBS Dissertations and Theses

As humans, we inhabit an environment shared with many microorganisms, some of which are harmless or beneficial, and others which represent a threat to our health. A complex network of organs, cells and their protein products form our bodies’ immune system, tasked with detecting these potentially harmful agents and eliminating them. This same system also serves to detect changes in the healthy balance of normal functions in the body, and for repairing tissue damage caused by injury. Immune recognition of nucleic acids, DNA and RNA, is one way that the body detects invading pathogens and initiates tissue repair. A number ...


Quantitative Analysis Of Novel Chemical And Shrna Based Methods To Increase Survival Of Motor Neuron Protein Levels, Matthew C. Evans Jun 2011

Quantitative Analysis Of Novel Chemical And Shrna Based Methods To Increase Survival Of Motor Neuron Protein Levels, Matthew C. Evans

GSBS Dissertations and Theses

Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder that is the leading genetic cause of infantile death. SMA is caused by homozygous deletion or mutation of the survival of motor neuron 1 gene (SMN1). The SMN2 gene is nearly identical to SMN1, however is alternatively spliced. The close relationship to SMN1 results in SMN2 being a very power genetic modifier of SMA disease severity and a target for therapies. In this study we attempt to characterize novel chemical compounds identified as potential activators of the SMN2 gene. Additionally, we sought to determine the regulatory role individual HDAC proteins ...


A Tale Of Two Snps: Polymorphism Analysis Of Toll-Like Receptor (Tlr) Adapter Proteins: A Dissertation, Kamalpreet Nagpal May 2011

A Tale Of Two Snps: Polymorphism Analysis Of Toll-Like Receptor (Tlr) Adapter Proteins: A Dissertation, Kamalpreet Nagpal

GSBS Dissertations and Theses

The innate immune system is the first line of defense against invading pathogens. Recognition of microbial ligands by the innate immune system relies on germ-line encoded, evolutionarily conserved receptors called pattern recognition receptors (PRRs). Toll-like receptors (TLRs) are one such family of PRRs and are involved in innate defenses to a variety of microbes. At the core of TLR signaling pathways are Toll interleukin-1 receptor (TIR) domain containing adapter proteins. Much of the specificity of TLR pathways arise from the differential use of these adapter proteins.

The TLR signaling cascade that ensues upon ligand recognition is marked by finely orchestrated ...


The Role Of Mir-21 And Mir-31 In Cellular Responses Mediated By Tgf-Β: A Dissertation, Charisa L. Cottonham May 2011

The Role Of Mir-21 And Mir-31 In Cellular Responses Mediated By Tgf-Β: A Dissertation, Charisa L. Cottonham

GSBS Dissertations and Theses

The function of transforming growth factor β (TGF-β) in cancer is notoriously complex. Initially TGF-β limits tumorigenesis, but at later stages in tumor progression TGF-β promotes the malignant spread of tumor cells. Past studies to understand the pro-metastasis utility of TGF-β centered upon its ability to regulate protein-coding genes. Recently, a small class of non-coding RNAs known as microRNAs (miRNAs) emerged as novel posttranscriptional regulators of gene expression. The significance of miRNA function in cellular processes from embryonic development to the maintenance of homeostasis in adult tissues is becoming increasingly clear. Also apparent is the strong association between aberrant miRNA ...


Hsp90-Mediated Maturation Of Kinases And Nuclear Steroid Hormone Receptors: A Dissertation, Natalie W. Pursell Apr 2011

Hsp90-Mediated Maturation Of Kinases And Nuclear Steroid Hormone Receptors: A Dissertation, Natalie W. Pursell

GSBS Dissertations and Theses

Among heat shock proteins, Hsp90 is unusual because it is not required for the proper folding of most cellular proteins but rather is disproportionally linked to the activation of signal transduction proteins including over forty kinases and many steroid hormone receptors. Mutated forms of many Hsp90 clients are causative agents in cancer, making Hsp90 a promising pharmacological target. Many small molecular inhibitors have been identified that competitively bind to the ATP binding site of Hsp90, some of which are in clinical trials as anticancer agents. Although the activation of kinase and hormone receptor clients by Hsp90 and its co-chaperones has ...


Molecular Mechanisms Of Pirna Biogenesis And Function In Drosophila: A Dissertation, Chengjian Li Apr 2011

Molecular Mechanisms Of Pirna Biogenesis And Function In Drosophila: A Dissertation, Chengjian Li

GSBS Dissertations and Theses

In the Drosophila germ line, PIWI-interacting RNAs (piRNAs) ensure genomic stability by silencing endogenous selfish genetic elements such as retrotransposons and repetitive sequences.

We examined the genetic requirements for the biogenesis and function of piRNAs in both female and male germ line. We found that piRNAs function through the PIWI, rather than the AGO, family Argonaute proteins, and the production of piRNAs requires neither microRNA (miRNA) nor small interfering RNA (siRNA) pathway machinery. These findings allowed the discovery of the third conserved small RNA silencing pathway, which is distinct from both the miRNA and RNAi pathways in its mechanisms of ...