Medical Sciences Commons^™

Anti-Argonaute Rip-Chip Shows That Mirna Transfections Alter Global Patterns Of Mrna Recruitment To Microribonucleoprotein Complexes, Wang-Xia Wang, Bernard R. Wilfred, Yanling Hu, Arnold J. Stromberg, Peter T. Nelson

Pathology and Laboratory Medicine Faculty Publications

MicroRNAs (miRNAs) play key roles in gene expression regulation by guiding Argonaute (AGO)-containing microribonucleoprotein (miRNP) effector complexes to target polynucleotides. There are still uncertainties about how miRNAs interact with mRNAs. Here we employed a biochemical approach to isolate AGO-containing miRNPs from human H4 tumor cells by co-immunoprecipitation (co-IP) with a previously described anti-AGO antibody. Co-immunoprecipitated (co-IPed) RNAs were subjected to downstream Affymetrix Human Gene 1.0 ST microarray analysis. During rigorous validation, the "RIP-Chip" assay identified target mRNAs specifically associated with AGO complexes. RIP-Chip was performed after transfecting brain-enriched miRNAs (miR-107, miR-124, miR-128, and miR-320) and nonphysiologic control miRNA to identify …

Proteomic Analysis Of Iron Acquisition, Metabolic And Regulatory Responses Of Yersinia Pestis To Iron Starvation, Rembert Pieper, Shih-Ting Huang, Prashanth P. Parmar, David J. Clark, Hamid Alami, Robert D. Fleischmann, Robert D. Perry, Scott N. Peterson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

BACKGROUND: The Gram-negative bacterium Yersinia pestis is the causative agent of the bubonic plague. Efficient iron acquisition systems are critical to the ability of Y. pestis to infect, spread and grow in mammalian hosts, because iron is sequestered and is considered part of the innate host immune defence against invading pathogens. We used a proteomic approach to determine expression changes of iron uptake systems and intracellular consequences of iron deficiency in the Y. pestis strain KIM6+ at two physiologically relevant temperatures (26°C and 37°C).

RESULTS: Differential protein display was performed for three Y. pestis subcellular fractions. Five characterized Y. pestis …

Neural Network Model For Instruments That Store And Retrieve Sequential Information, Philip W. Landfield, Olivier Thibault

Pharmacology and Nutritional Sciences Faculty Patents

A method and design is provided for distributing and storing sets of temporally ordered information in a systematic and sequential fashion. This method is based on a model of how the brain functions in the distribution and storage of temporally ordered memories, but it can also be applied to the design of new biological, electronic or optical devices. These devices may be used in the testing and development of new therapeutic drugs, in the detection of toxic agents or impaired performance, or in the development of new industrial and consumer devices in which the orderly storage of sequential information is …

Mir-107 Is Reduced In Alzheimer's Disease Brain Neocortex: Validation Study, Peter T. Nelson, Wang-Xia Wang

Pathology and Laboratory Medicine Faculty Publications

MiR-107 is a microRNA (miRNA) that we reported previously to have decreased expression in the temporal cortical gray matter early in the progression of Alzheimer's disease (AD). Here we study a new group of well-characterized human temporal cortex samples (N=19). MiR-107 expression was assessed, normalized to miR-124 and let-7a. Correlation was observed between decreased miR-107 expression and increased neuritic plaque counts (P< 0.05) and neurofibrillary tangle counts (P< 0.02) in adjacent brain tissue. Adjusted miR-107 and BACE1 mRNA levels tended to correlate negatively (trend with regression P< 0.07). In sum, miR-107 expression tends to be lower relative to other miRNAs as AD progresses.

Characterization And Optimization Of Microelectrode Arrays For Glutamate Measurements In The Rat Hippocampus, Pooja Mahendra Talauliker

University of Kentucky Doctoral Dissertations

An overarching goal of the Gerhardt laboratory is the development of an implantable neural device that allows for long-term glutamate recordings in the hippocampus. Proper L-glutamate regulation is essential for hippocampal function, while glutamate dysregulation is implicated in many neurodegenerative diseases. Direct evidence for subregional glutamate regulation is lacking in previous in vivo studies because of limitations in the spatio-temporal resolution of conventional experimental techniques. We used novel enzyme-coated microelectrode arrays (MEAs) for rapid measurements (2Hz) of extracellular glutamate in urethane-anesthetized rats. Potassium-evoked glutamate release was highest in the cornu ammonis 1 (CA1) subregion and lowest in the cornu ammonis …

Studies Of The Effects Of Dopamine Neuron Stimulating Peptides In Rodent Models Of Normal And Dysfunctional Dopaminergic Systems, Joshua Lee Fuqua

University of Kentucky Doctoral Dissertations

A theoretical post-translational processing model of the proprotein form of glial cell line-derived neurotrophic factor (GDNF) likely produces three biologically active peptides. The three prospective peptides formed are 5, 11, and 17 amino acid peptides, entitled dopamine neuron stimulating peptide -5 (DNSP-5), -11 (DNSP-11), and -17 (DNSP-17), respectively. The DNSPs were hypothesized to increase dopaminergic neuron function because of their relationship to GDNF: a molecule with established neurotrophic actions on dopaminergic neurons. The DNSPs have the potential to provide a therapeutic molecule similar to GDNF, but with increased ease of delivery and improved bioavailability.

Neurochemical effects of DNSPs were examined …

The Role Of The L-Type Calcium Channel And Its Carboxyl-Terminus, Miranda Jean Byse

University of Kentucky Doctoral Dissertations

In the heart, the primary role of the L-type calcium channel (LTCC) Ca_V1.2 is to conduct calcium into cardiomyocytes and initiate contraction. However, part of the Ca_V1.2 channel itself, the cleaved carboxyl-terminus (CCt) can also localize to the nucleus and regulate gene transcription. Therefore, the goal of this dissertation project was to determine the role and regulation of CCt in the embryonic and adult heart. The global hypothesis of my dissertation project is that CCt localizes to the nucleus in embryonic and adult cardiomyocytes via a calcium-mediated mechanism and regulates transcription. A model of pharmacological LTCC …

Structural Instability Of Human Ribosomal Rna Gene Clusters, Dawn Michelle Stults

University of Kentucky Doctoral Dissertations

The human ribosomal RNA genes are critically important for cell metabolism and viability. They code for the catalytic RNAs which, encased in a housing of more than 80 ribosomal proteins, link together amino acids by peptide bonds to generate all cellular proteins. Because the RNAs are not repeatedly translated, as is the case with messenger RNAs, multiple copies are required. The genes which code for the human ribosomal RNAs (rRNAs) are arranged as clusters of tandemly repeated sequences. Three of four catalytic RNAs are spliced from a single transcript. The genes are located on the short arms of the five …

The Radiosensitization Effect Of Parthenolide In Prostate Cancer: Implications For Selective Cancer Killing By Modulation Of Intracellular Redox State, Yulan Sun

University of Kentucky Doctoral Dissertations

Parthenolide (PN), a major active component of the traditional herbal medicine feverfew, has been shown to have anti-inflammatory and anti-tumor properties. More remarkably, the cytotoxicity of PN seems selective to tumor cells but not their normal cell counterparts. In the present study, we investigate whether and how PN selectively enhances tumor sensitivity to radiation therapy by using prostate cancer cells LNCaP, DU145 and PC3, as well as normal prostate epithelial cells PrEC.

Our study demonstrates that inhibition of NF-κB pathway and suppression of its downstream target MnSOD are common mechanisms for the radiosensitization effect of PN in prostate cancer cells. …

Local Synaptic Network Interactions In The Dentate Gyrus Of A Cortical Contusion Model Of Posttraumatic Epilepsy, Robert F. Hunt Iii

University of Kentucky Doctoral Dissertations

Posttraumatic epilepsy is a common consequence of brain trauma. However, little is known about how long-term changes in local excitatory and inhibitory synaptic networks contribute to epilepsy after closed-head brain injury. This study adapted a widely used model of experimental brain injury as a mouse model of posttraumatic epilepsy. Behavioral seizure activity and alterations in synaptic circuitry in the dentate gyrus were examined in mice after experimental cortical contusion brain injury. Spontaneous behavioral seizures were observed in 20% of mice after moderate injury and 36-40% of mice weeks after severe injury. In the dentate gyrus, most mice displayed regionally localized …

Development Of Novel Ahr Antagonists, Hyosung Lee

University of Kentucky Doctoral Dissertations

Aryl hydrocarbon receptor (AHR) is a sensor protein, activated by aromatic chemical species for transcriptionally regulating xenobiotic metabolizing enzymes. AHR is also known to be involved in a variety of pathogenesis such as cancer, diabetes mellitus, cirrhosis, asthma, etc. The AHR signaling induced by xenobiotics has been intensively studied whereas its physiological role in the absence of xenobiotics is poorly understood. Despite a number of ligands of AHR have been reported thus far, further applications are still hampered by the lack of specificity and/or the partially agonistic activity. Thus, a pure AHR antagonist is needed for deciphering the AHR cryptic …

Neural Mechanisms Of Sympathetic Activation During Hyperinsulinemia And Obesity-Induced Hypertension, Megan Elyse Bardgett

University of Kentucky Doctoral Dissertations

Obesity afflicts more than 30% of the U.S. population and is a major risk factor for the development of hypertension, type II diabetes, and cardiovascular disease. Studies in humans and animals indicate that obesity is associated with increased sympathetic outflow to the vasculature and kidneys. One mechanism postulated to underlie the increase in sympathetic nerve activity (SNA) in obesity is hyperinsulinemia. Little is known regarding the central circuitry underlying elevated SNA and arterial blood pressure (ABP) during hyperinsulinemia and obesity or if sympathoexcitatory circuits are still responsive to insulin in obesity.

Hyperinsulinemic-euglycemic clamps elevate SNA to the hind limb vasculature …

Biochemical Characterization Of Human Mismatch Recognition Proteins Mutsα And Mutsβ, Lei Tian

University of Kentucky Doctoral Dissertations

The integrity of an organism's genome depends on the fidelity of DNA replication and the efficiency of DNA repair. The DNA mismatch repair (MMR) system, which is highly conserved from prokaryotes to eukaryotes, plays an important role in maintaining genome stability by correcting base-base mismatches and insertion/deletion (ID) mispairs generated during DNA replication and other DNA transactions. Mismatch recognition is a critical step in MMR. Two mismatch recognition proteins, MutSα (MSH2-MSH6 heterodimer) and MutSβ (MSH2-MSH3 heterodimer), have been identified in eukaryotic cells. MutSα and MutSβ have partially overlapping functions, with MutSα recognizing primarily base-base mismatches and 1-2 nt ID mispairs …

Explorations In Homeoviscous Adaptation And Mass Spectral Analysis Of Membrane Lipids, Michael Douglas Timmons

University of Kentucky Doctoral Dissertations

The focus of this dissertation is centered on the mass spectral analysis of lipids and changes occurring in keeping with the concept of homeoviscous adaptation [1]. Homeoviscous adaptation is the process of modification of membrane lipids in response to environmental stimuli [1]. Dissertation investigations applied this concept to prokaryotic and eukaryotic organisms, and expanded the perception of environmental factors from exogenous organic solvents to intracellular environment.

The field of lipidomics deals with the analysis of phospholipid and fatty acid components of membranes the changes that occur due to environmental stimuli and their biological significance [2-6]. The high sensitivity of mass …

Function Of Androgen Receptor In Prostate Cancer Epithelial Mesenchymal Transition And Microtubule Targeting, Menglei Zhu

University of Kentucky Doctoral Dissertations

Prostate cancer is the most frequently diagnosed non-skin cancer and the third leading cause of cancer mortality among men in the US. Androgens are functionally required for the normal growth of the prostate gland and play a critical role in prostate tumor development and progression. Epithelial-mesenchymal-transition (EMT) is an important process during normal development, and cancer cell metastasis.

This study examined the ability of androgens to influence EMT of prostate cancer epithelial cells and evaluate the effect of taxol chemotherapy on androgen signaling in prostate cancer cells in prostate cancer. The EMT pattern was evaluated on the basis of expression …

Anomalous Constitutive Src Kinase Activity Promotes B Lymphoma Survival And Growth, Jiyuan Ke, R. Lakshman Chelvarajan, Vishal Sindhava, Darrell A. Robertson, Lazaros Lekakis, C. Darrell Jennings, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Background: Previously we have shown that B cell receptor (BCR) expression and B cell receptor signaling pathways are important for the basal growth of B lymphoma cells. In particular we have shown that the activation of Syk, a non-src family protein tyrosine kinase and the mitogen activated protein kinases (MAPK), ERK and JNK that mediate BCR signals are required for the constitutive growth of B lymphoma cells. Since src family protein tyrosine kinases (SFKs) like Lyn are known to be needed for the phosphorylation of BCR co-receptors, Ig-alpha and Ig-beta, we hypothesized that one or more SFKs will be constitutively …

Apolipoprotein E But Not B Is Required For The Formation Of Infectious Hepatitis C Virus Particles, Jieyun Jiang, Guangxiang Luo

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Our previous studies have found that hepatitis C virus (HCV) particles are enriched in apolipoprotein E (apoE) and that apoE is required for HCV infectivity and production. Studies by others, however, suggested that both microsomal transfer protein (MTP) and apoB are important for HCV production. To define the roles of apoB and apoE in the HCV life cycle, we developed a single-cycle HCV growth assay to determine the correlation of HCV assembly with apoB and apoE expression, as well as the influence of MTP inhibitors on the formation of HCV particles. The small interfering RNA (siRNA)-mediated knockdown of apoE expression …

Detection Of Sub-Clinical Cwd Infection In Conventional Test-Negative Deer Long After Oral Exposure To Urine And Feces From Cwd+ Deer, Nicholas J. Haley, Candace K. Mathiason, Mark D. Zabel, Glenn C. Telling, Edward A Hoover

Microbiology, Immunology, and Molecular Genetics Faculty Publications

BACKGROUND: Chronic wasting disease (CWD) of cervids is a prion disease distinguished by high levels of transmissibility, wherein bodily fluids and excretions are thought to play an important role. Using cervid bioassay and established CWD detection methods, we have previously identified infectious prions in saliva and blood but not urine or feces of CWD+ donors. More recently, we identified very low concentrations of CWD prions in urine of deer by cervid PrP transgenic (Tg[CerPrP]) mouse bioassay and serial protein misfolding cyclic amplification (sPMCA). This finding led us to examine further our initial cervid bioassay experiments using sPMCA.

OBJECTIVES: We sought …

Jnk1 Activation Predicts The Prognostic Outcome Of The Human Hepatocellular Carcinoma, Qingshan Chang, Jianguo Chen, Kevin J. Beezhold, Vince Castranova, Xianglin Shi, Fei Chen

Toxicology and Cancer Biology Faculty Publications

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide with an extremely poor prognosis. The classification of HCC based on the molecular signature is not well-established.

RESULTS: In the present study, we reported HCC signature genes based on the JNK1 activation status in 31 HCC specimens relative to the matched distal noncancerous liver tissue from 31 patients. The HCCs with high JNK1 (H-JNK1) and low JNK1 (L-JNK1) were sub-grouped. Two different signature gene sets for both H-JNK1 and L-JNK1 HCC were identified through gene expression profiling. A striking overlap of signature genes was observed between the H-JNK1 …

Cd19 Signaling Is Impaired In Murine Peritoneal And Splenic B-1 B Lymphocytes, Trivikram Dasu, Vishal Sindhava, Stephen H. Clarke, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

B-1 cells reside predominantly within the coelomic cavities, tonsils, Peyer's patches, spleen (a minor fraction – ∼5%) and are absent in the lymph nodes. They are the primary sources of natural IgM in the body. B-1 cells express polyreactive B cell receptors (BCRs) that cross react with self-antigens and are thus implicated in auto-immune disorders. Previously, we reported that peritoneal B-1 cells are deficient in CD19-mediated intracellular signals leading to Ca²⁺ mobilization. Here, we find that splenic B-1 cells, like peritoneal B-1 cells, are defective in Ca²⁺ release upon B cell activation by co-cross-linking BCR and CD19. In …

Lipid Nanoparticles With Accessible Nickel As A Vaccine Delivery System For Single And Multiple His-Tagged Hiv Antigens, Weili Yan, Anekant Jain, Ronan O'Carra, Jerold Woodward, Wenxue Li, Guanhan Li, Avindra Nath, Russell J. Mumper

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Lipid-based nanoparticles (NPs) with a small amount of surface-chelated nickel (Ni-NPs) were developed to easily formulate the HIV his-tagged Tat protein, as well as to formulate and co-deliver two HIV antigens (his-p24 and his-Nef) on one particle. Female BALB/c mice were immunized by s.c. injection with his-Tat/Ni-NP formulation (1.5 μg Tat-his/mouse) and control formulations on day 0 and 14. The day 28 anti-Tat specific IgG titer with his-Tat/Ni-NP was significantly greater than that with Alum/his-Tat. Furthermore, splenocytes from his-Tat/Ni-NP immunized mice secreted significantly higher IFN-γ than those from mice immunized with Alum/his-Tat. Although Ni-NPs did not show better adjuvant activity …

Dna-Binding By Haemophilus Influenzae And Escherichia Coli Ybab, Members Of A Widely-Distributed Bacterial Protein Family, Anne E. Cooley, Sean P. Riley, Keith Kral, M. Clarke Miller, Edward Demoll, Michael G. Fried, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

BACKGROUND: Genes orthologous to the ybaB loci of Escherichia coli and Haemophilus influenzae are widely distributed among eubacteria. Several years ago, the three-dimensional structures of the YbaB orthologs of both E. coli and H. influenzae were determined, revealing a novel "tweezer"-like structure. However, a function for YbaB had remained elusive, with an early study of the H. influenzae ortholog failing to detect DNA-binding activity. Our group recently determined that the Borrelia burgdorferi YbaB ortholog, EbfC, is a DNA-binding protein. To reconcile those results, we assessed the abilities of both the H. influenzae and E. coli YbaB proteins to bind DNA …

Metallic Nickel Nano- And Fine Particles Induce Jb6 Cell Apoptosis Through A Caspase-8/Aif Mediated Cytochrome C-Independent Pathway, Jinshun Zhao, Linda Bowman, Xingdong Zhang, Xianglin Shi, Binghua Jiang, Vincent Castranova, Min Ding

Toxicology and Cancer Biology Faculty Publications

BACKGROUND: Carcinogenicity of nickel compounds has been well documented. However, the carcinogenic effect of metallic nickel is still unclear. The present study investigates metallic nickel nano- and fine particle-induced apoptosis and the signal pathways involved in this process in JB6 cells. The data obtained from this study will be of benefit for elucidating the pathological and carcinogenic potential of metallic nickel particles.

RESULTS: Using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, we found that metallic nickel nanoparticles exhibited higher cytotoxicity than fine particles. Both metallic nickel nano- and fine particles induced JB6 cell apoptosis. Metallic nickel nanoparticles produced higher apoptotic induction than fine …

Monoclonal Antibody 1a7 And Use For The Treatment Of Melanoma And Small Cell Carcinoma, Malaya Chatterjee, Kenneth A. Foon, Sunil K. Chatterjee

Microbiology, Immunology and Molecular Genetics Faculty Patents

The present invention relates to monoclonal antibody 1A7. This is an anti-idiotype produced by immunizing with an antibody specific for ganglioside GD2, and identifying a hybridoma secreting antibody with immunogenic potential in a multi-step screening process. Also disclosed are polynucleotide and polypeptide derivatives based on 1A7, including single chain variable region molecules and fusion proteins, and various pharmaceutical compositions. When administered to an individual, the 1A7 antibody overcomes immune tolerance and induces an immune response against GD2, which comprises a combination of anti-GD2 antibody and GD2-specific T cells. The invention further provides methods for treating a disease associated with altered …

Characterization Of Conserved Properties Of Hemagglutinin Of H5n1 And Human Influenza Viruses: Possible Consequences For Therapy And Infection Control, Veljko Veljkovic, Nevena Veljkovic, Claude P. Muller, Sybille Müller, Sanja Glisic, Vladimir Perovic, Heinz Köhler

Microbiology, Immunology, and Molecular Genetics Faculty Publications

BACKGROUND: Epidemics caused by highly pathogenic avian influenza virus (HPAIV) are a continuing threat to human health and to the world's economy. The development of approaches, which help to understand the significance of structural changes resulting from the alarming mutational propensity for human-to-human transmission of HPAIV, is of particularly interest. Here we compare informational and structural properties of the hemagglutinin (HA) of H5N1 virus and human influenza virus subtypes, which are important for the receptor/virus interaction.

RESULTS: Presented results revealed that HA proteins encode highly conserved information that differ between influenza virus subtypes H5N1, H1N1, H3N2, H7N7 and defined an …

Borrelia Burgdorferi Ebfc Defines A Newly-Identified, Widespread Family Of Bacterial Dna-Binding Proteins, Sean P. Riley, Tomasz Bykowski, Anne E. Cooley, Logan H. Burns, Kelly Babb, Catherine A. Brissette, Amy Bowman, Matthew L. Rotondi, M. Clarke Miller, Edward Demoll, Kap Lim, Michael G. Fried, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The Lyme disease spirochete, Borrelia burgdorferi, encodes a novel type of DNA-binding protein named EbfC. Orthologs of EbfC are encoded by a wide range of bacterial species, so characterization of the borrelial protein has implications that span the eubacterial kingdom. The present work defines the DNA sequence required for high-affinity binding by EbfC to be the 4 bp broken palindrome GTnAC, where ‘n’ can be any nucleotide. Two high-affinity EbfC-binding sites are located immediately 5′ of B. burgdorferi erp transcriptional promoters, and binding of EbfC was found to alter the conformation of erp promoter DNA. Consensus EbfC-binding …

Detection Of Cwd Prions In Urine And Saliva Of Deer By Transgenic Mouse Bioassay, Nicholas J. Haley, Davis M. Seelig, Mark D. Zabel, Glenn C. Telling, Edward A. Hoover

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Chronic wasting disease (CWD) is a prion disease affecting captive and free-ranging cervids (e.g. deer, elk, and moose). The mechanisms of CWD transmission are poorly understood, though bodily fluids are thought to play an important role. Here we report the presence of infectious prions in the urine and saliva of deer with chronic wasting disease (CWD). Prion infectivity was detected by bioassay of concentrated, dialyzed urine and saliva in transgenic mice expressing the cervid PrP gene (Tg[CerPrP] mice). In addition, PrP(CWD) was detected in pooled and concentrated urine by protein misfolding cyclic amplification (PMCA). The concentration of abnormal prion protein …

Integral And Peripheral Association Of Proteins And Protein Complexes With Yersinia Pestis Inner And Outer Membranes, Rembert Pieper, Shih-Ting Huang, David J. Clark, Jeffrey M. Robinson, Hamid Alami, Prashanth P. Parmar, Moo-Jin Suh, Srilatha Kuntumalla, Christine L. Bunai, Robert D. Perry, Robert D. Fleischmann, Scott N. Peterson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Yersinia pestis proteins were sequentially extracted from crude membranes with a high salt buffer (2.5 M NaBr), an alkaline solution (180 mM Na2CO3, pH 11.3) and membrane denaturants (8 M urea, 2 M thiourea and 1% amidosulfobetaine-14). Separation of proteins by 2D gel electrophoresis was followed by identification of more than 600 gene products by MS. Data from differential 2D gel display experiments, comparing protein abundances in cytoplasmic, periplasmic and all three membrane fractions, were used to assign proteins found in the membrane fractions to three protein categories: (i) integral membrane proteins and peripheral membrane proteins with low solubility in …

Dna Instability In Replicating Huntington's Disease Lymphoblasts, Milena Cannella, Vittorio Maglione, Tiziana Martino, Giuseppe Ragona, Luigi Frati, Guo-Min Li, Ferdinando Squitieri

Toxicology and Cancer Biology Faculty Publications

BACKGROUND: The expanded CAG repeat in the Huntington's disease (HD) gene may display tissue-specific variability (e.g. triplet mosaicism) in repeat length, the longest mutations involving mitotic (germ and glial cells) and postmitotic (neurons) cells. What contributes to the triplet mutability underlying the development of HD nevertheless remains unknown. We investigated whether, besides the increased DNA instability documented in postmitotic neurons, possible environmental and genetic mechanisms, related to cell replication, may concur to determine CAG repeat mutability. To test this hypothesis we used, as a model, cultured HD patients' lymphoblasts with various CAG repeat lengths.

RESULTS: Although most lymphoblastoid cell lines …

Role Of Mel-18 In Regulating Protein Sumoylation And Identification Of A New Polymorphism In Bmi-1, Jie Zhang

University of Kentucky Doctoral Dissertations

Small ubiquitin-like modifier (SUMO) regulates numerous biological functions. In a previous study we found that sumoylation of HSF2 is involved in regulating HSF2 bookmarking function, but the mechanism that mediates this regulation was unknown. The results in my work support the intriguing hypothesis that polycomb protein, Mel-18, actually functions as an anti-SUMO E3 protein, interacting both with HSF2 and the SUMO E2 Ubc9, but acting to inhibit Ubc9 activity and thereby decrease sumoylation of the HSF2.

This study also suggested that Mel-18 negatively regulates the sumoylation of other cellular proteins, and we extend its targets to RanGAP1 protein. The results …