Design, Synthesis And Development Of Transporter Targeting Agents For Image-Guided Therapy And Drug Delivery,
2013
The University of Texas Graduate School of Biomedical Sciences at Houston
Design, Synthesis And Development Of Transporter Targeting Agents For Image-Guided Therapy And Drug Delivery, Ning Tsao
The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences Dissertations and Theses (Open Access)
The purpose of this study was to design, synthesize and develop novel transporter targeting agents for image-guided therapy and drug delivery. Two novel agents, N4-guanine (N4amG) and glycopeptide (GP) were synthesized for tumor cell proliferation assessment and cancer theranostic platform, respectively. N4amG and GP were synthesized and radiolabeled with 99mTc and 68Ga. The chemical and radiochemical purities as well as radiochemical stabilities of radiolabeled N4amG and GP were tested. In vitro stability assessment showed both 99mTc-N4amG and 99mTc-GP were stable up to 6 hours, whereas 68Ga-GP was stable up to 2 hours. Cell culture studies …
Divergent Protein Motifs Direct Ef-P Mediated Translational Regulation In Salmonella And Escherichia Coli,
2013
University of Toronto
Divergent Protein Motifs Direct Ef-P Mediated Translational Regulation In Salmonella And Escherichia Coli, Steven J. Hersch, Mengchi Wang, S. Betty Zou, Kyung-Mee Moon, Leonard J. Foster, Michael Ibba, William Wiley Navarre
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Elongation factor P (EF-P) is a universally conserved bacterial translation factor homologous to eukaryotic/archaeal initiation factor 5A. In Salmonella, deletion of the efp gene results in pleiotropic phenotypes, including increased susceptibility to numerous cellular stressors. Only a limited number of proteins are affected by the loss of EF-P, and it has recently been determined that EF-P plays a critical role in rescuing ribosomes stalled at PPP and PPG peptide sequences. Here we present an unbiased in vivo investigation of the specific targets of EF-P by employing stable isotope labeling of amino acids in cell culture (SILAC) to compare the …
Polyamine-Anthracene Conjugates: The Correlation Between Interaction With Dna, Pat Activity, And Cytotoxicity,
2013
Georgia State University
Polyamine-Anthracene Conjugates: The Correlation Between Interaction With Dna, Pat Activity, And Cytotoxicity, Khoa T. Nguyen
Georgia State Undergraduate Research Conference
No abstract provided.
Dicer-2 Processes Diverse Viral Rna Species,
2013
University of Pennsylvania
Dicer-2 Processes Diverse Viral Rna Species, Leah R Sabin, Qi Zheng, Pramod Thekkat, Jamie Yang, Gregory J. Hannon, Brian D. Gregory, Matthew Tudor, Sara Cherry
Departmental Papers (Biology)
RNA silencing pathways play critical roles in gene regulation, virus infection, and transposon control. RNA interference (RNAi) is mediated by small interfering RNAs (siRNAs), which are liberated from double-stranded (ds)RNA precursors by Dicer and guide the RNA-induced silencing complex (RISC) to targets. Although principles governing small RNA sorting into RISC have been uncovered, the spectrum of RNA species that can be targeted by Dicer proteins, particularly the viral RNAs present during an infection, are poorly understood. Dicer-2 potently restricts viral infection in insects by generating virus-derived siRNAs from viral RNA. To better characterize the substrates of Dicer-2, we examined the …
Biosynthetic Pathway Of The Aminoribosyl Component Of Lipopeptidyl Nucleoside Antibiotics,
2013
University of Kentucky
Biosynthetic Pathway Of The Aminoribosyl Component Of Lipopeptidyl Nucleoside Antibiotics, Xiuling Chi
Theses and Dissertations--Pharmacy
Several lipopeptidyl nucleoside antibiotics that inhibit bacterial translocase I (MraY) involved in peptidoglycan cell wall biosynthesis contain an aminoribosyl moiety, an unusual sugar appendage in natural products. A-90289 and muraminomicin are the two representative antibiotics that belong to this family. Bioinformatic analysis of the biosynthetic A-90289 gene clusters revealed that five enzymes are likely involved in the assembly and attachment of the aminoribosyl unit. These enzymes of A-90289 are functionally assigned by in vitro characterization. The results reveal a unique ribosylation pathway that highlighted by uridine-5′-monophosphate as the source of the sugar, a phosphorylase strategy to generate a sugar-1-phosphate, and …
(R)-Β-Lysine Modified Elongation Factor P Functions In Translation Elongation,
2012
The Ohio State University
(R)-Β-Lysine Modified Elongation Factor P Functions In Translation Elongation, Tammy J. Bullwinkle, S. Betty Zou, Andrei Rajkovic, Steven J. Hersch, Sara Elgamal, Nathaniel Robinson, David Smil, Yuri Bolshan, William Wiley Navarre, Michael Ibba
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Post-translational modification of bacterial elongation factor P (EF-P) with (R)-β-lysine at a conserved lysine residue activates the protein in vivo and increases puromycin reactivity of the ribosome in vitro. The additional hydroxylation of EF-P at the same lysine residue by the YfcM protein has also recently been described. The roles of modified and unmodified EF-P during different steps in translation, and how this correlates to its physiological role in the cell, have recently been linked to the synthesis of polyproline stretches in proteins. Polysome analysis indicated that EF-P functions in translation elongation, rather than initiation as proposed previously. This was …
Circularized Synthetic Oligodeoxynucleotides Serve As Promoterless Rna Polymerase Iii Templates For Small Rna Generation In Human Cells,
2012
CUNY City College
Circularized Synthetic Oligodeoxynucleotides Serve As Promoterless Rna Polymerase Iii Templates For Small Rna Generation In Human Cells, Christine I. Seidl, Lodoe Lama, Kevin Ryan
Publications and Research
Synthetic RNA formulations and viral vectors are the two main approaches for delivering small therapeutic RNA to human cells. Here we report findings supporting an alternative strategy in which an endogenous human RNA polymerase (RNAP) is harnessed to make RNA hairpin-containing small RNA from synthetic single-stranded DNA oligonucleotides. We report that circularizing a DNA template strand encoding a pre-microRNA hairpin mimic can trigger its circumtranscription by human RNAP III in vitro and in human cells. Sequence and secondary structure preferences that appear to promote productive transcription are described. The circular topology of the template is required for productive transcription, at …
Selection Of Trna Charging Quality Control Mechanisms That Increase Mistranslation Of The Genetic Code,
2012
The Ohio State University
Selection Of Trna Charging Quality Control Mechanisms That Increase Mistranslation Of The Genetic Code, Srujana S. Yadavalli, Michael Ibba
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Mistranslation can follow two events during protein synthesis: production of non-cognate amino acid:transfer RNA (tRNA) pairs by aminoacyl-tRNA synthetases (aaRSs) and inaccurate selection of aminoacyl-tRNAs by the ribosome. Many aaRSs actively edit non-cognate amino acids, but editing mechanisms are not evolutionarily conserved, and their physiological significance remains unclear. To address the connection between aaRSs and mistranslation, the evolutionary divergence of tyrosine editing by phenylalanyl-tRNA synthetase (PheRS) was used as a model. Certain PheRSs are naturally error prone, most notably a Mycoplasma example that displayed a low level of specificity consistent with elevated mistranslation of the proteome. Mycoplasma PheRS was found …
Regulatory Impact Of Rna Secondary Structure Across The Arabidopsis Transcriptome,
2012
University of Pennsylvania
Regulatory Impact Of Rna Secondary Structure Across The Arabidopsis Transcriptome, Fan Li, Lee E. Vandivier, Matthew R. Willmann, Ying Chen, Brian D. Gregory
Departmental Papers (Biology)
The secondary structure of an RNA molecule plays an integral role in its maturation, regulation, and function. However, the global influence of this feature on plant gene expression is still largely unclear. Here, we use a high-throughput, sequencing-based, structure-mapping approach in conjunction with transcriptome-wide sequencing of rRNA-depleted (RNA sequencing), small RNA, and ribosome-bound RNA populations to investigate the impact of RNA secondary structure on gene expression regulation in Arabidopsis thaliana. From this analysis, we find that highly unpaired and paired RNAs are strongly correlated with euchromatic and heterochromatic epigenetic histone modifications, respectively, providing evidence that secondary structure is necessary …
Taking Aim At The Start Of Translation,
2012
The Ohio State University
Taking Aim At The Start Of Translation, Medha Raina, Michael Ibba
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
No abstract provided.
Spatial And Functional Relationships Among Pol V-Associated Loci, Pol Iv-Dependent Sirnas, And Cytosine Methylation In The Arabidopsis Epigenome,
2012
University of Michigan-Ann Arbor
Spatial And Functional Relationships Among Pol V-Associated Loci, Pol Iv-Dependent Sirnas, And Cytosine Methylation In The Arabidopsis Epigenome, Andrzej T. Wierzbicki, Ross Cocklin, Anoop Mayampurath, Ryan Lister, M. J. Rowley, Brian D. Gregory, Joseph R. Ecker, Haixu Tang, Craig S. Pikaard
Departmental Papers (Biology)
Multisubunit RNA polymerases IV and V (Pols IV and V) mediate RNA-directed DNA methylation and transcriptional silencing of retrotransposons and heterochromatic repeats in plants. We identified genomic sites of Pol V occupancy in parallel with siRNA deep sequencing and methylcytosine mapping, comparing wild-type plants with mutants defective for Pol IV, Pol V, or both Pols IV and V. Approximately 60% of Pol V-associated regions encompass regions of 24-nucleotide (nt) siRNA complementarity and cytosine methylation, consistent with cytosine methylation being guided by base-pairing of Pol IV-dependent siRNAs with Pol V transcripts. However, 27% of Pol V peaks do not overlap sites …
A Pseudo-Trna Modulates Antibiotic Resistance In Bacillus Cereus,
2012
The Ohio State University
A Pseudo-Trna Modulates Antibiotic Resistance In Bacillus Cereus, Theresa E. Rogers, Sandro F. Ataide, Kiley Dare, Assaf Katz, Stephanie Seveau, Hervé Roy, Michael Ibba
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Bacterial genomic islands are often flanked by tRNA genes, which act as sites for the integration of foreign DNA into the host chromosome. For example, Bacillus cereus ATCC14579 contains a pathogenicity island flanked by a predicted pseudo-tRNA, tRNAOther, which does not function in translation. Deletion of tRNAOther led to significant changes in cell wall morphology and antibiotic resistance and was accompanied by changes in the expression of numerous genes involved in oxidative stress responses, several of which contain significant complementarities to sequences surrounding tRNAOther. This suggested that tRNAOther might be expressed as part of a larger RNA, and RACE analysis …
Savor: A Server For Sequencing Annotation And Visualization Of Rna Structures,
2012
University of Pennsylvania
Savor: A Server For Sequencing Annotation And Visualization Of Rna Structures, Fan Li, Paul Ryvkin, Daniel M. Childress, Otto Valladares, Brian D. Gregory, Li-San Wang
Departmental Papers (Biology)
RNA secondary structure is required for the proper regulation of the cellular transcriptome. This is because the functionality, processing, localization and stability of RNAs are all dependent on the folding of these molecules into intricate structures through specific base pairing interactions encoded in their primary nucleotide sequences. Thus, as the number of RNA sequencing (RNA-seq) data sets and the variety of protocols for this technology grow rapidly, it is becoming increasingly pertinent to develop tools that can analyze and visualize this sequence data in the context of RNA secondary structure. Here, we present Sequencing Annotation and Visualization of RNA structures …
Association Of A Multi-Synthetase Complex With Translating Ribosomes In The Archaeon Thermococcus Kodakarensis,
2012
The Ohio State University
Association Of A Multi-Synthetase Complex With Translating Ribosomes In The Archaeon Thermococcus Kodakarensis, Medha Raina, Sara Elgamal, Thomas J. Santangelo, Michael Ibba
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
In archaea and eukaryotes aminoacyl-tRNA synthetases (aaRSs) associate in multi-synthetase complexes (MSCs), however the role of such MSCs in translation is unknown. MSC function was investigated in vivo in the archaeon Thermococcus kodakarensis, wherein six aaRSs were affinity co-purified together with several other factors involved in protein synthesis, suggesting that MSCs may interact directly with translating ribosomes. In support of this hypothesis, the aminoacyltRNA synthetase (aaRS) activities of the MSC were enriched in isolated T. kodakarensis polysome fractions. These data indicate that components of the archaeal protein synthesis machinery associate into macromolecular assemblies in vivo and provide the potential …
Chemosensitization Of Hepatocellular Carcinoma To Gemcitabine By Non-Invasive Radiofrequency Field-Induced Hyperthermia,
2012
The University of Texas Graduate School of Biomedical Sciences at Houston
Chemosensitization Of Hepatocellular Carcinoma To Gemcitabine By Non-Invasive Radiofrequency Field-Induced Hyperthermia, Mustafa Raoof
The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences Dissertations and Theses (Open Access)
Gemcitabine is a potent nucleoside analogue against solid tumors however drug resistance rapidly emerges. Removal of gemcitabine incorporated in the DNA by repair mechanisms could potentially contribute to resistance in chemo-refractory solid tumors. In this study, we evaluated homologous recombination repair of gemcitabine-stalled replication forks as a potential mechanism contributing to resistance. We also studied the effect of hyperthermia on homologous recombination pathway to explain the previously reported synergy between gemcitabine and hyperthermia. We found that hyperthermia degrades and inhibits localization of Mre11 to gemcitabine-stalled replication forks. Furthermore, gemcitabine-treated cells that were also treated with hyperthermia demonstrate a prolonged passage …
Cryo-Em Structure Of The Archaeal 50s Ribosomal Subunit In Complex With Initiation Factor 6 And Implications For Ribosome Evolution,
2012
ETH Zurich
Cryo-Em Structure Of The Archaeal 50s Ribosomal Subunit In Complex With Initiation Factor 6 And Implications For Ribosome Evolution, Basil J. Greber, Daniel Boehringer, Vlatka Godinic-Mikulcic, Ana Crnkovic, Michael Ibba, Ivana Weygand-Durasevic, Nenad Ban
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Translation of mRNA into proteins by the ribosome is universally conserved in all cellular life. The composition and complexity of the translation machinery differ markedly between the three domains of life. Organisms from the domain Archaea show an intermediate level of complexity, sharing several additional components of the translation machinery with eukaryotes that are absent in bacteria. One of these translation factors is initiation factor 6 (IF6), which associates with the large ribosomal subunit. We have reconstructed the 50S ribosomal subunit from the archaeon Methanothermobacter thermautotrophicus in complex with archaeal IF6 at 6.6 Å resolution using cryo-electron microscopy (EM). The …
Global Analysis Of Rna Secondary Structure In Two Metazoans,
2012
University of Pennsylvania
Global Analysis Of Rna Secondary Structure In Two Metazoans, Fan Li, Qi Zheng, Paul Ryvkin, Isabelle Dragomir, Yaanik Desai, Subhadra Aiyer, Otto Valladares, Jamie Yang, Shelley Bambina, Leah R Sabin, John I. Murray, Todd Lamitina, Arjun Rai, Sara Cherry, Li-San Wang, Brian D. Gregory
Departmental Papers (Biology)
The secondary structure of RNA is necessary for its maturation, regulation, processing, and function. However, the global influence of RNA folding in eukaryotes is still unclear. Here, we use a high-throughput, sequencing-based, structure-mapping approach to identify the paired (double-stranded RNA [dsRNA]) and unpaired (single-stranded RNA [ssRNA]) components of the Drosophila melanogaster and Caenorhabditis elegans transcriptomes, which allows us to identify conserved features of RNA secondary structure in metazoans. From this analysis, we find that ssRNAs and dsRNAs are significantly correlated with specific epigenetic modifications. Additionally, we find key structural patterns across protein-coding transcripts that indicate that RNA folding demarcates regions …
Roles Of Trna In Cell Wall Biosynthesis,
2012
The Ohio State University
Roles Of Trna In Cell Wall Biosynthesis, Kiley Dare, Michael Ibba
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Recent research into various aspects of bacterial metabolism such as cell wall and antibiotic synthesis, degradation pathways, cellular stress, and amino acid biosynthesis has elucidated roles of aminoacyl‐transfer ribonucleic acid (aa‐tRNA) outside of translation. Although the two enzyme families responsible for cell wall modifications, aminoacyl‐phosphatidylglycerol synthases (aaPGSs) and Fem, were discovered some time ago, they have recently become of intense interest for their roles in the antimicrobial resistance of pathogenic microorganisms. The addition of positively charged amino acids to phosphatidylglycerol (PG) by aaPGSs neutralizes the lipid bilayer making the bacteria less susceptible to positively charged antimicrobial agents. Fem transferases utilize …
A Proposal To Test The Effects Of Factor Ecat1 On Pluripotency, From Reprogramming To Differentiation Of Human Somatic Cells,
2012
Scripps College
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 …
Solution Structure And Dna-Binding Properties Of The Phosphoesterase Domain Of Dna Ligase D,
2011
CUNY City College
Solution Structure And Dna-Binding Properties Of The Phosphoesterase Domain Of Dna Ligase D, Aswin Natarajan, Kaushik Dutta, Deniz B. Temel, Pravin A. Nair, Stewart Shuman, Ranajeet Ghose
Publications and Research
The phosphoesterase (PE) domain of the bacterial DNA repair enzyme LigD possesses distinctive manganese-dependent 3'-phosphomonoesterase and 3'-phosphodiesterase activities. PE exemplifies a new family of DNA end-healing enzymes found in all phylogenetic domains. Here, we determined the structure of the PE domain of Pseudomonas aeruginosa LigD (PaePE) using solution NMR methodology. PaePE has a disordered N-terminus and a well-folded core that differs in instructive ways from the crystal structure of a PaePE•Mn(2+)• sulfate complex, especially at the active site that is found to be conformationally dynamic. Chemical shift perturbations in the presence of primertemplate duplexes with 30-deoxynucleotide, …
