Biology Commons^™

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 …

Postzygotic Isolation In Drosophila Simulans And D. Mauritiana, Christopher T. D. Dickman

Electronic Thesis and Dissertation Repository

The study of speciation requires examination of barriers that produce and maintain species separation. Using Drosophila simulans and D. mauritiana, this thesis focuses on post-zygotic isolating mechanisms, which occur after the formation of interspecies hybrids. This study aims to examine the genetic causes of male hybrid sterility and decreased hybrid female lifespan. Quantitative trait locus (QTL) mapping using flies with an attached-X chromosome, identified seven autosomal QTLs that contribute to hybrid sterility. Separately, reduction in hybrid female lifespan was noted for females bearing an attached-X chromosome and was more severe in individuals who were mated. This reduction is caused …

Signaling Pathways And Genetic Interactions That Lead To Metastatic Cancer In Drosophila Melanogaster, Amanda Cole

Renée Crown University Honors Thesis Projects - All

Cancer is a complex and multigenic disease, which is typically initiated by genetic mutations in tumor suppressor genes that regulate homeostatic mechanisms within cells. Oncogenic promoter mutations, like those involved in signal transduction pathways, also have the potential to induce cancer in an otherwise healthy organism. Transformation is highly dependent upon mutations to both tumor suppressor and oncogenes, as neither mutation is exclusive in its ability to generate malignant tumors. In the model organism, Drosophila melanogaster, I have generated metastatic cancer through the genetic effect of overactive Raf signaling, in conjugation with silencing selected tumor suppressor genes using RNA …

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 …

Pomc Is Expressed In Pancreatic Alpha Cells, Samia M.M Farrara

Electronic Theses and Dissertations

Pancreatic alpha cells secrete glucagon to increase blood glucose during hypoglycemia. Currently, the mechanisms that initiate glucagon secretion are not well understood. This study investigates the expression of pro-opiomelanocortin (POMC), a potent regulator of glucagon secretion, in alpha cells.

Insulin tolerance tests in mice lacking the POMC gene showed a correlation between alpha MSH, and glucagon secretion from alpha cells (Hochgeschwender et al. 2003). Results from a previous study showed that the POMC product, melanocortin á-MSH, acts through a melanocortin receptor 4 (MC4R) at the surface of the alpha cells to trigger the release of glucagon [Angleson, unpublished data, Lumsden …