Biochemistry, Biophysics, and Structural Biology Commons^™

Novel Role Of Erbb-2 In Inhibition Of Jagged-1-Mediated Trans-Activation Of Notch In Breast Cancer, Kinnari Pandya

Dissertations

The ErbB-2 gene is amplified and the resulting protein product overexpressed in 15-30% of breast tumors, and associated with aggressive behavior and poor overall survival. Currently, there are two FDA approved therapies targeting ErbB-2 for the treatment of ErbB-2 positive breast cancer: trastuzumab, a humanized monoclonal antibody is directed against the extracellular domain of ErbB-2 and lapatinib, a dual EGFR/ErbB-2 tyrosine kinase inhibitor. Unfortunately, anti-ErbB-2 therapy resistance remains a major problem in metastatic breast cancer. Our data suggested that gene amplification or overexpression of ErbB-2 inhibits Notch-1 transcriptional activity and trastuzumab or lapatinib increased

Notch-1 transcriptional activity. Furthermore, Notch-1 is …

Significance Of Protein Interactions In Mediating Af9 Function, Bhavna Malik

Dissertations

Rearrangements of the MLL gene at chromosome band 11q23 have been associated with a heterogeneous group of lymphoid, myeloid and mixed lineage leukemias. MLL rearrangements occur approximately in 70% of infant leukemias and are also common in therapy-related leukemias where patients were previously treated with topoisomerase II inhibitors. Unfortunately, these patients have a poor prognosis. MLL gene rearrangements give rise to chimeric proteins that contain the N-terminal portion of MLL fused to the C-terminal portion of over 50 different fusion partners. The chimeric proteins cause constitutive expression of some MLL target genes such as HOXA9 and MEIS1, and enhanced proliferation …

Molecular Functions Of Mll Phd3 Binding To Its Ligands Cyp33 And H3k4me3, Gayathree Raman

Dissertations

Mixed Lineage Leukemia protein (MLL) is required for proper embryonic development, and hematopoiesis. It is a SET domain containing histone methyl transferase that trimethylates histone H3 on lysine 4 (H3K4Me3), a histone modification that correlates with active transcription. The 3rd PHD finger of MLL binds to H3K4me3. Thus MLL is a "writer" with an embedded "reader" for H3K4Me3. Cyp33 is another known ligand of MLL PHD3. Over expression of Cyp33 results in transcriptional repression of MLL target genes.

The aim of this study is to determine the biological function of MLL PHD3 binding to H3K4Me3 or Cyp33. Cyp33 binding to …

A Study Of The Therapeutic Potential Of Af4 Mimetic Peptides, Nisha N. Barretto

Dissertations

Mixed lineage leukemias (MLL) are a group of acute and aggressive leukemias. They account for over 70% of infant leukemias, and 10% of acute adult leukemias. Pediatric ALL and therapy related MLL leukemias carry poor prognosis in spite of several advancement in the field of leukemia research. Therefore, new therapies for MLL leukemias are needed.

Majority of MLL leukemias arise due to the balanced translocations of the MLL gene. As a result of these translocations, chimeric MLL fusion proteins are expressed. The most frequently occurring MLL fusion proteins are known to aberrantly recruit the super elongation complex (SEC) resulting in …

Biophysical Characterization Of Tryptophan Locales, Mg²+ Binding And Protein Folding In Gα Subunits, Matthew Najor

Dissertations

The objective of this study is to understand the structure of guanine nucleotide - binding (G) proteins using a variety of spectroscopic tools. G proteins are membrane-bound proteins consisting of α, β, and γ subunits required for the transduction of extracellular signals to various intracellular effectors. Activation of G protein coupled receptors by neurotransmitters or hormones result in a conformational change of a G protein that is triggered by the exchange of guanosine 5'- diphosphate (GDP) bound to the  subunit for guanosine 5'- triphosphate (GTP) and concomitant dissociation of the  dimer.

Wild type (WT) Giα1 has three tryptophan …

Critical Functions Specified By The Mll Cxxc Domain Determine Leukemogenic Capacity, Noah Warren Birch

Dissertations

TheMixed Lineage Leukemia(MLL) gene can participate in chromosomal translocations which generate a fusion protein leading to acute leukemia. A better understanding of how MLL fusion proteins contribute to leukemia is necessary in order to develop more effective treatments. In my dissertation project, I investigated the functional role of amino acids within the MLL CXXC domain to determine how specific residues contribute to leukemogenic capacity.

MLL fusion proteins retain the amino-terminal portion of MLL including the CXXC DNA-binding domain while the carboxy-terminal portion is comprised of a fusion partner. The closest homolog of MLL, MLL2 (alternatively named MLL4), also contains a …

Targeting The Notch-1/Igf-1r/Akt Axis In At Orthotopic Model Of Advanced Non-Small Cell Lung Cancer, Shuang Liang

Dissertations

Lung cancer is the leading cause of cancer death in the U.S. and worldwide. The most frequent type of lung cancer is non-small cell lung cancer (NSCLC). NSCLC is mostly diagnosed at advanced stages (stage IIIB 18% of cases, stage IV 40% of cases) due to the lack of effective early detection methods. Thus, the discovery of alternative therapeutic strategies is of extreme importance.

Others and we have previously found that Notch signaling plays a crucial role in NSCLC. Our preliminary results indicate that Notch-1 provides necessary survival signals to NSCLC cells by positively regulating IGF-1R to activate the Akt-1 …

Molecular Mechanisms Regulating Chemokine Receptor Cxcr4 Signaling And Trafficking, Rohit Malik

Dissertations

CXCR4 is a G protein-coupled receptor (GPCR) that binds to the chemokine, stromal cell-derived factor-1 (SDF-1alpha; a.k.a. CXCL12). The SDF-1alpha/CXCR4 signaling axis plays an essential role during embryogenesis in the development of the heart, brain and vasculature and in the adult mediating immune cell trafficking and stem cell homing to the bone marrow. Dysregulation of SDF-1alpha/CXCR4 signaling is linked to several pathological conditions, including cardiovascular disease, immunological disorders as well as cancer growth and metastasis. However, the mechanisms that govern CXCR4 signaling remain poorly understood. In this dissertation project, we attempt to further our understanding of the molecular mechanisms that …

The Role Of Cyp33 In Mll Mediated Gene Repression, Steven D. Poppen

Dissertations

Mixed Lineage Leukemia (MLL) is a multidomain protein whose gene is translocated in a subset of AML leukemias. Translocation of the MLL gene is present in approximately five percent of adult acute leukemias and ten percent of pediatric leukemias (Daser, A 2004, Look, A 1997, Huret, J 2001) Patients presenting in the clinic at the time of diagnosis with an MLL fusion have been shown to respond poorly to treatment and have a worse prognosis than matched wild type MLL patients (Rubnitz, J 1994, Rubnitz, J 1999). Novel therapies therefore are needed in order to more effectively treat patients with …

The Binding Properties And Functional Consequences Of Ryr2-Cam Interaction, Yi Yang

Dissertations

The aim of my dissertation is to understand the regulation of RyR2. The whole dissertation is composed of two parts. The first part focused on RyR2-CaM interaction. The second focused on synthetic RyR2 domain peptide (DPc10), which worked as a powerful molecular tool for RyR2 functional and structural studies.

CaM has been long identified as an important cardiac RyR regulator. Broad studies suggest CaM is a critical RyR2 stabilizer and CaM-RyR2 interaction is a critical molecular substrate for arrhythmias and HF pathogenesis, but the in situ binding properties for CaM-RyR2 are still unknown. Here we, Using FRET detection and permeabilized …

Determination Of An Interaction Between Nipped B-Like Protein And Mll, Adam Robert Marek

Master's Theses

The Mixed Lineage Leukemia (MLL) protein serves as a positive transcriptional regulator during hematopoietic and embryonic development. The MLL gene can undergo chromosomal translocations producing leukemia-causing fusions that retain the MLL amino-terminus, including the repression domain. A recent yeast two-hybrid screening used the MLL repression domain as bait and yielded nine positive clones of Nipped B-like (NIPBL).

NIPBL is a crucial member of the cohesin complex, which functions in the segregation of sister chromatids during cell division. However, recent evidence suggests the cohesin complex can also function as a transcriptional regulator.

In this study, we wanted to confirm this interaction …

Characterization Of The Coca Chemokine Receptor Four Agonist Activity Of Ubiquitin, Daniel M. Staren

Master's Theses

Ubiquitin has previously been identified as another natural agonist of CXC chemokine receptor 4 (CXCR4). In addition, recent evidence suggests that ubiquitin may activate CXCR4 through a binding site on the receptor, which is distinct from the binding site for the cognate ligand stromal cell-derived factor (SDF)-1α. The cellular consequences of ubiquitin induced CXCR4 activation, however, are still poorly defined and a side-by-side comparison of CXCR4 mediated functions after activation with SDF-1α and ubiquitin is lacking. Such information will be instrumental to better understand the physiological function of CXCR4 and to further define its role as a therapeutic target in …

Role Of Notch Signaling In T Cell Polarization, Shilpa Keerthivasan

Dissertations

The differentiation of CD4+ T cells to different effector lineages in response to pathogenic stimuli is the core of the adaptive immune system. One of the effector subsets recently discovered is Thelper 17 (Th17) and it plays a predominant role in autoimmune diseases and inflammatory disorders.

In my thesis, I aimed to study the role of Notch cell surface receptors in Th17 differentiation. Using in vitro Th17 differentiation assays of human naïve CD4+ T cells, I have shown that Notch signaling, particularly Notch1, plays a crucial role in Th17 polarization. By using pharmacological inhibitors and specific knockdown of Notch1, I …

Repression Of Protein Kinase C Delta In Human Squamous Cell Carcinomas By Ras, Fyn And Nf-Kappa B Signaling, Vipin Yadav

Dissertations

The delta isoform of Protein Kinase C (PKC-delta) is widely expressed in many normal tissues, including epidermal keratinocytes, and has a critical role in UV-induced apoptosis. However, PKC-delta is frequently lost in chemically or UV-induced mouse skin tumors, as well as in human cutaneous squamous cell carcinomas (SCC). Furthermore, re-expression of PKC-delta in human SCC lines is sufficient to induce apoptosis and suppress tumorigenicity, making PKC-delta a potential tumor suppressor gene for SCCs. The objective of this dissertation is to investigate the mechanism of PKC-delta loss in human SCCs.

To determine the mechanism of PKC-delta loss in human SCCs, we …

The Specific Role Of The Mll Cxxc Domain In Mll Fusion Protein Function, Laurie Ellen Risner

Dissertations

The MLL gene was first identified because it is involved in chromosome translocations which produce novel fusion proteins that cause leukemia. The CXXC domain of MLL is a cysteine rich DNA binding domain with specificity for binding unmethylated CpG-containing DNA. The CXXC domain is retained in oncogenic MLL fusions, and is absolutely required for the fusions to cause leukemia. This project explored the role of the CXXC domain by introducing structure-informed point mutations within the MLL CXXC domain that disrupt DNA binding, and by performing domain swap experiments in which different CXXC domains from other proteins, including DNMT1, CGBP and …

Role Of Non-Coding Rna Nc4 In Mll And Cyp33 Mediated Regulation Of Hoxc8, Jessica Arvindbhai Solanki

Dissertations

MLL or Mixed Lineage Leukemia gene is clinically known for its involvement in genetic translocation with more than 70 different partners identified each giving rise to a highly leukemogenic fusion protein. With a poor prognosis of MLL related leukemia, an investigation into its role during hematopoiesis has been a very active field of research. In order to design strategies to combat the MLL leukemia, it becomes essential to delineate the molecular mechanisms behind the function of MLL wild type protein. Wild type MLL is a transcriptional maintenance protein from the Trithorax Group (TrxG) that resides in complex with other chromatin …

Wee1 Is A Biological Target Of The Mir-17-92 Cluster In Leukemia, Sonia Susan Olikara

Master's Theses

MicroRNAs are noncoding RNAs that bind to the 3' untranslated region of their mRNA targets, which causes downregulation of target gene expression. Previous studies have shown that the miR-17-92 cluster, which encodes six miRNAs, is overexpressed in leukemias arising from chromosomal translocations of the Mixed Lineage Leukemia (MLL) gene. In the present study, prediction algorithms identified WEE1, a kinase that inhibits cell cycle progression, as a possible target of five of the six miRNAs. Through luciferase reporter assays, we found that miR-17, miR-20a, and miR-18a specifically target nucleotides 465 to 487 of the 3' UTR of WEE1, while miR-19a and …

Notch-1 Specifically Activates Erk1/2 In Multiple Breast Cancer Subtypes, Allison Schuyler Rogowski

Master's Theses

Notch-1 is a cell fate regulatory protein and a potent breast oncogene. Notch-1 and its ligand Jagged-1 are over-expressed in human breast cancers that are associated with poor overall survival (Reedijk, Odorcic et al. 2005). Deregulated Notch signaling may contribute to tumorigenesis by increasing proliferation, inhibiting differentiation, and preventing apoptosis (Miele, Golde et al. 2006). The mitogen-activated protein kinase (MAPK) pathway is a critical cell signaling pathway that has been implicated in the development and progression of cancer (Hanahan and Weinberg 2000). Four major MAPK pathways are involved in both cell growth and apoptosis. The regulation of these pathways is …

The Role Of Igf-1 And Notch Signaling In Thoracic Malignancies., Sandra Eliasz

Dissertations

Thoracic malignancies are one of the deadliest of all cancers, being the leading cause of cancer death in the Western world. Thoracic malignancies arise from different tissues; however the most common are of epithelial (commonly referred to as non-small cell lung cancer, or NSCLC), neuroendocrine (small cell lung cancer, or SCLC) and mesothelial origin (malignant mesothelioma, or MM). The DNA oncogenic virus Simian Virus 40 (SV40) has been shown to cooperate with environmental oncogenic fibers in the onset of MM. Insulin like growth factor-1 (IGF-1) signaling plays a central role in all thoracic malignancies and in the process of SV40-mediated …

New Cyclophanes As Supramolecular Scaffolds: The Synthesis Of Tribenzo-1,4,7-Triazacyclononatriene., Andria M. Panagopoulos

Dissertations

Supramolecular chemistry involves the formation of complex molecular entities that have the capacity to participate in specific molecular recognition of guest molecules. A commonly employed scaffold in supramolecular chemistry is the trimeric crown-shaped molecule cyclotriveratrylene (CTV). CTV has been studied extensively for its capability of binding a number of smaller organic and organometallic guests within its bowl-shaped cleft and has been used as a building block enabling the construction of more complex cryptophanes. The goal of this research is the synthesis and characterization of a novel cyclophane, tribenzo-1,4,7-triazacyclononene and derivatives thereof. These new cyclophanes should have greater versatility than the …

Polyomavirus Enhancer Activator 3 (Pea3), A Member Of The Ets Family Of Transcription Factors, Is A Transcriptional Activator Of Notch-1 And Notch-4 In Breast Cancer: An Opportunity For Novel Combinational Therapy, Anthony George Clementz

Dissertations

Women diagnosed with triple-negative breast cancer have the worst overall prognosis and frequently present with metastatic tumors. To date, there are no targeted therapies available to combat this aggressive form of breast cancer due to the lack of expression of well-known targets such as ER-alpha, PR, or HER2/neu. Therefore, there is an immediate need to identify novel targets that are responsible for the proliferation, survival, and invasive phenotype. Notch-1 and Notch-4, both potent breast oncogenes, are overexpressed in triple-negative breast cancers-associated with the poorest overall survival. PEA3 (polyomavirus enhancer activator 3), a member of the Ets family of transcription factors, …

The Distribution Of Gnrh And Erbeta In Pre- And Post-Pubertal Male Rats, Maysaa Nageeb

Master's Theses

The hypothalamic-pituitary- gonadal axis is intrinsic in regulating reproductive function. Each part orchestrates the synthesis and release of a key hormone. At the level of the hypothalamus, Gonadotropin- releasing hormone (GnRH) is released and it is the

most upstream regulator of sexual maturation. GnRH neurons express a type of estrogen receptor, ERbeta, which suggests that estradiol (E2) plays a direct role in modulating GnRH function (Herbison and Pape 2001). The objective of this study was to determine if gonadal steroid hormones regulate the expression of ERbeta and GnRH mRNA in the male brain during pubertal development. In-situ hybridization was used …

Developmental Characterization Of Cara Mitad: A Drosophila Nuclear Receptor Co-Regulator, Chhavi Chauhan

Dissertations

In insects and vertebrates, hormone titers drive cellular proliferation and differentiation events that guide proper development. Nuclear receptors (NR) respond to these hormone signals by activating cascades of gene expression, along with coregulator protein complexes. In Drosophila melanogaster, fluctuating titers of the steroid hormone ecdysone are responsible for coordinating the timing of organismal development. Despite major advances in our understanding of Drosophila NR activities, we lack essential knowledge of the coregulators that are required for their proper function.

We have recently identified the Drosophila cara mitad (cmi) (`dear half') gene. The deduced CMI protein is closely related to the N-terminal …

Lysine Specific Demethylase-1 And The Brahma Chromatin Remodeling Complex Regulate Conserved Signaling Pathways During Drosophila Wing Development, Brenda Jean Curtis

Dissertations

The conserved SWI/SNF chromatin remodeling complex uses the energy from ATP hydrolysis to alter local chromatin environments by disrupting DNA-histone contacts. The Drosophila SWI/SNF counterpart, the Brahma complex, has been shown to have an essential role in regulating the proper expression of many developmentally important genes, including those required for eye and wing tissue morphogenesis. A temperature sensitive mutation in one of the core subunits, SNR1 (SNF5/Ini1/SMARC B1), results in reproducible wing patterning phenotypes that can be enhanced and suppressed by extragenic mutations. SNR1 functions as a regulatory subunit to modulate chromatin remodeling activities of the Brahma complex on target …

Localization And Functional Analysis Of Plasmodium Falciparum Genes Pfl2550w And Pff0750w, Carolyn Jane Strobel

Master's Theses

Malaria is a parasitic disease that causes over a million deaths worldwide each year. Understanding development through the parasite's life cycle is necessary to stop disease transmission. As the genetic basis for the crucial transition from the erythrocytic asexual cycle to gametocytogenesis is unknown, we hope to better understand this transition by studying sexual stage genes and their roles in gametocytogenesis. PFL2550w and PFF0750w are genes upregulated during gametocytogenesis that were identified by a whole-genome microarray comparing gene expression between gametocyte-producing and gametocyte-deficient strains. In this study, PFL2550w was shown to be a soluble protein that is exported from the …

Structure-Function Relationship Studies Of The Udp-Glucose Pyrophosphorylase From Escherichia Coli, Agnieszka Maria Orlof

Master's Theses

UDP-Glucose Pyrophosphorylase (UDP-Glc PPase) is a key enzyme of the carbohydrate metabolic pathway widely used among prokaryotes and eukaryotes. In plants, UDP-Glc PPase is necessary for sucrose synthesis while mammals utilize this enzyme for the production of glycogen. A bacterium such as Escherichia coli uses UDP-Glc PPase for biosynthesis of the lipopolysscharide core which forms a cell wall.

This study focused on UDP-Glc PPase from Escherichia coli which is encoded by both galU and galF genes. The first part of this project investigated amino acids that could play an important role in the function of UDP Glc PPase (GalU). Based …

The Electrophysiological Effects Of Acute Thyroid Hormone Exposure On Atrial Myocytes, Jon Paul Fiening

Dissertations

No abstract provided.

Genetic Analysis Of The Nuo Locus That Encodes The Proton Translocating Nadh Dehydrogenase In Escherichia Coli, Holly Jennifer Falk-Krzesinski

Dissertations

No abstract provided.

Singlet-Oxygen-Mediated Inactivation Of Acetylcholinesterase: A Comparison Of Purified Enzyme In Solution And Enzyme Bound To K562 Leukemia Cells, Gail D. Deadwyler

Dissertations

No abstract provided.

Analysis Of The Mechanisms Controlling Phospholipid Biosynthetic Gene Expression In The Yeast Saccharomyces Cerevisiae, Brian Patrick Ashburner

Dissertations

No abstract provided.