Biochemistry, Biophysics, and Structural Biology Commons^™

Evolution Of Repetitive Proteins: Spider Silks From Nephila Clavipes (Tetragnathidae) And Araneus Bicentenarius (Araneidae), Richard D. Beckwitt, Steven Arcidiacono, Robert Stote

Richard D Beckwitt

Spider silks are highly repetitive proteins, characterized by regions of polyalanine and glycine-rich repeating units. We have obtained two variants of the Spidroin 1 (NCF-1) silk gene sequence from Nephila clavipes. One sequence (1726 bp) was from a cloned cDNA, and the other (1951 bp) was from PCR of genomic DNA. When these sequences are compared with each other and the previously published Spidroin 1 sequence, there are differences due to sequence rearrangements, as well as single base substitutions. These variations are similar to those that have been reported from other highly repetitive genes, and probably represent the results …

The Role Of The Arched Helicases In Exosome-Mediated Function, A. Alejandra Klauer

Dissertations & Theses (Open Access)

RNA processing and degradation are two important functions that control gene expression and promote RNA fidelity in the cell. A major ribonuclease complex, called the exosome, is involved in both of these processes. The exosome is composed of ten essential proteins with only one catalytically active subunit, called Rrp44. While the same ten essential subunits make up both the nuclear and cytoplasmic exosome, there are nuclear and cytoplasmic exosome cofactors that promote specific exosome functions in each of the cell compartments. To date, it is unclear how the exosome distinguishes between RNA substrates. We hypothesize that compartment specific cofactors may …

Tet1: A Unique Dna Demethylase For Maintenance Of Dna Methylation Pattern, Chunlei Jin

Dissertations & Theses (Open Access)

DNA methylation at the C5 position of cytosine (5-methylcytosine, 5mC) is a crucial epigenetic modification of the genome and has been implicated in numerous cellular processes in mammals, including embryonic development, transcription, X chromosome inactivation, genomic imprinting and chromatin structure. Like histone modifications, DNA methylation is also dynamic and reversible. However, in contrast to well defined DNA methyltransferases, the enzymes responsible for erasing DNA methylation still remain to be studied. The ten-eleven translocation family proteins (TET1/2/3) were recently identified as Fe(II)/2-oxoglutarate (2OG)-dependent 5mC dioxygenases, which consecutively convert 5mC into 5-hydroxymethylcytosine (5hmC), 5-formylcytosine and 5-carboxylcytosine both in vitro and in mammalian …

A Genetic, Transgenic, And Transcriptomic Analysis Of Larval Salivary Gland Physiology In Drosophila Melanogaster, Elana A. Paladino

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cholesterol is the precursor to a unique class of lipophilic signaling molecules called steroid hormones that initiate the development of sexual characteristics, reactions to stress, and maintenance of metabolism, among many other functions. Although much progress has been made in understanding the function of these signaling hormones, we do not fully understand how a single steroid can cause many distinct, tissue-specific responses. Drosophila melanogaster is an effective model for understanding steroid hormone action because of its simplicity. The steroid molting hormone 20-hydroxyecdysone (hereafter, 20E) is the primary active steroid in Drosophila and mediates not only larval molts and the emergence …

Transcriptional Cross Talk Within The Mar-Sox-Rob Regulon In Escherichia Coli Is Limited To The Rob And Marrab Operons, Lon Chubiz, George Glekas, Christopher Rao

Biology Department Faculty Works

Bacteria possess multiple mechanisms to survive exposure to various chemical stresses and antimicrobial compounds. In the enteric bacterium Escherichia coli, three homologous transcription factors—MarA, SoxS, and Rob—play a central role in coordinating this response. Three separate systems are known to regulate the expression and activities of MarA, SoxS, and Rob. However, a number of studies have shown that the three do not function in isolation but rather are coregulated through transcriptional cross talk. In this work, we systematically investigated the extent of transcriptional cross talk in the mar-sox-rob regulon. While the three transcription factors were found to have the potential …

Mutation And Complementation Of A Cellulose Synthase (Cesa) Gene, Ahmed Y. El-Araby

Senior Honors Projects

Cellulose is a carbohydrate polymer that is composed of repeating glucose subunits. Being the most abundant organic compound in the biosphere and comprising a large percentage of all plant biomass, cellulose is extremely plentiful and has a significant role in nature. Cellulose is present in plant cell walls, in commercial products such as those made from wood or cotton, and is of interest to the biofuel industry as a potential alternative fuel source. Although indigestible by humans, cellulose is nutritionally valuable, serving as a dietary fiber. Because of its ubiquity and importance in many areas, studying cellulose will prove to …

Heterotopic Ossification: Cellular Basis, Symptoms, And Treatment, Brian Wolfe

Senior Honors Theses

Heterotopic ossification (HO) is the process by which calcified bone develops in soft tissues. Because of the abnormal calcification, complications such as bone deformation, loss of range of motion, and joint immobility adversely affect patients. There are many genetic types of heterotopic ossification, namely fibrodysplasia ossificans progressiva, progressive osseous heteroplasia, and Albright hereditary osteodystrophy. However, this condition can also arise from surgery, burns, or traumatic injuries, so it is seen as an important area for research in the future. There are various treatments available such as non-steroidal anti-inflammatory drugs and radiation therapy, as well as combinations of the two. The …

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

Theses and Dissertations in Biomedical Sciences

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

Western blot analysis …

Mechanistic Studies Of A Novel Ppar-Gamma Mutant That Causes Lipodystrophy And Diabetes, Olga Astapova

Wayne State University Dissertations

PPAR-gamma is a nuclear receptor that plays a central role in metabolic regulation by regulating extensive gene expression networks in adipose, liver, skeletal muscle and many other tissues. Human PPAR-gamma mutations are rare and cause a monogenetic form of severe type II diabetes with metabolic syndrome, known as familiar partial lypodystrophy. The E157D PPAR-gamma mutant causes atypical lipodystrophy in a large Canadian kindred, presenting with multiple musculoskeletal, neurological and hematological abnormalities in addition to the classic lipodystrophy features of insulin-resistant diabetes, hypertension and dyslipidemia. This mutation is localized to the p-box of PPAR-gamma, a small region that interacts directly with …

Genetic Control Of A Central Pattern Generator: Rhythmic Oromotor Movement In Mice Is Controlled By A Major Locus Near Atp1a2, Steven J. St. John, John D. Boughter Jr, Megan K. Mulligan, Kenichi Tokita, Lu Lu, Detlef H. Heck, Robert W. Williams

Faculty Publications

calreticulin, Animals, Chromosome Mapping, Mammalian Chromosomes, Gene Expression Regulation, Genetic Linkage, Genome-Wide Association Study. Inbred C57BL Mice, Inbred DBA Mice, Quantitative Trait Loci, Sodium-Potassium-Exchanging ATPase/genetics, Atp1a2 protein, Sodium-Potassium-Exchanging ATPase, feeding behavior, drinking behavior, mice, central pattern generator, genetic control

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

Wayne State University Dissertations

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

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

The Role Of Chromatin And Cofactors In The Transcriptional Memory Effect Exerted In Saccharomyces Cerevisiae, Emily Leigh Paul

Legacy Theses & Dissertations (2009 - 2024)

Abf1 and Rap1 are functionally similar general regulatory factors (GRFs) found in Saccharomyces cerevisiae . Abf1, in its role as a transcriptional activator, exerts a memory effect on some genes under its control. This effect results in transcription levels remaining steady when Abf1 dissociates from its binding site in a conditional mutant. In contrast, Rap1 fails to elicit the same effect on its regulatory targets. Transcriptional memory effects have been observed in many fields of study, including immunology, cancer, and stem cells, and conservation of transcription machinery will allow studies in yeast to be applied to higher organisms.

The Role Of Ess1 In Survival, Morphogenetic Switching And Transcription In The Fungal Pathogen Candida Albicans, Dhanushki Poornima Samaranayake

Legacy Theses & Dissertations (2009 - 2024)

Candida albicans is a fungal pathogen that causes serious infections among immune-compromised patients and premature infants. C. albicans can become drug resistant, therefore, identifying new antifungal drug targets is an important goal. Here, we study a peptidyl-prolyl cis/trans isomerase called Ess1 as a potential drug target. Ess1 is conserved among pathogenic fungi, and therefore, potential inhibitors of Ess1 should display a broad spectrum of activity. We confirm that Ess1 is essential for growth in Candida albicans, but unlike the previously published find, deleting one copy of the C. albicans ESS1 gene did not affect morphogenetic switching. However, further reducing activity …

Expansion Dating: Calibrating Molecular Clocks In Marine Species From Expansions Onto The Sunda Shelf Following The Last Glacial Maximum, Eric D. Crandall, Elizabeth J. Sbrocco, Timery S. Deboer, Paul H. Barber, Kent E. Carpenter

Biological Sciences Faculty Publications

The rate of change in DNA is an important parameter for understanding molecular evolution and hence for inferences drawn from studies of phylogeography and phylogenetics. Most rate calibrations for mitochondrial coding regions in marine species have been made from divergence dating for fossils and vicariant events older than 1-2 My and are typically 0.5-2% per lineage per million years. Recently, calibrations made with ancient DNA (aDNA) from younger dates have yielded faster rates, suggesting that estimates of the molecular rate of change depend on the time of calibration, decaying from the instantaneous mutation rate to the phylogenetic substitution rate. aDNA …