Disrupting Monoallelic Expression Of Variant Surface Glycoprotein In Trypanosoma Brucei By A Non-Lethal Mutation In Class I Transcription Factor A, Sarah Platt

Honors Scholar Theses

Human African trypanosomiasis (HAT) is a lethal disease caused by protozoan hemoflagellates of the genus Trypanosoma. Humans are vulnerable to two subspecies, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. At the crux of HAT lethality lie two uncommon genetic expression phenomena: monoallelic expression and antigenic variation. Combined, these mechanisms effectively shield trypanosomes from host immune systems, prolonging infections. Variant Surface Glycoproteins (VSGs) are the key outer membrane proteins involved in antigenic variation. By continuously changing the composition of cell surface antigens, trypanosomes can survive bouts of immunological detection and eventually traverse the blood-brain barrier. There are over two …

Single-Fluorophore Sensors For Mechanical Force In Living Cells, Sarah Kricheff

Honors Scholar Theses

Mechanotransduction is the process by which a mechanical stimulus is converted to a cellular signal. This process is heavily influential of cell morphology, differentiation, and behavior. However, altered levels of mechanical stimuli are also found in many pathological contexts. For example, cancerous cells have stiffer surrounding tissue than healthy cells, and research suggests that this alters cell behavior and promotes metastasis. Despite these findings, the cellular processes behind these signaling alterations remain widely unknown. Understanding these cascades is critical, as involved proteins can give us a deeper understanding of the role of mechanotransduction, and certain proteins can potentially be targeted …

An Analysis Of Crispr-Cas Gene Editing In Agriculture, Ashley Laliberte

Honors Scholar Theses

The CRISPR-Cas system is a promising form of gene editing, especially for the agriculture industry. The ability to make single-nucleotide edits within a gene of interest, without the need to introduce foreign DNA, is a powerful tool for designing healthier and more efficient crops and food animals. This system provides opportunity for increased nutritional value, decreased food waste, and more economically and environmentally sustainable food production. Though this biotechnology is facing mechanistic limitations due to off-target effects and inefficient homology-directed repair, vast improvements have already been made to improve its efficacy. The CRISPR-Cas system is already the most advanced form …

Modeling And Analyzing An Optogenetic System For Photoactivatable Protein Dissociation, Anvin Thomas, James Schaff

Honors Scholar Theses

Computational modeling of cell-cell interactions can grant clues and can answer questions about an experiment, especially for observations about binding interactions and kinetics. This approach was used to investigate an interaction between a light-oxygen-voltage (LOV) domain and an engineered protein called Zdark (Zdk). The LOV domain is membrane-bound while Zdk is cytosolic. The LOV domain and Zdk bind strongly in dark (K_d 26.2 nM), and weakly upon exposure to blue light (K_d > 4 μM). Total internal reflection fluorescence (TIRF) images are acquired of Zdk, the fluorescent species bound to a mCherry tag, and the loss of fluorescence is …

The Ush2a Gene: An Analysis Of Ultrasonic Vocalizations In A Mouse Model Of Usher Syndrome Type 2, Kiana R. Akhundzadeh

Honors Scholar Theses

Usher syndrome type 2 is a complex autosomal recessive genetic disorder that is characterized by moderate to severe congenital sensorineural hearing loss, the onset of retinitis pigmentosa in the second decade of life, and in some cases, vestibular dysfunction. Mutations in the USH2A gene account for 85% of cases of type 2. The USH2A gene is responsible for encoding the protein usherin, which has an important role in the development and function of inner ear hair cells and retinal photoreceptors. Until recently, it has been believed that carriers of the USH2A mutation were phenotype free. However, recent data has suggested …

Identification, Characterization, And Life Cycle Of Intein-Associated Homing Endonucleases, Joshua J. Skydel

Honors Scholar Theses

Inteins are molecular parasites that have been identified in unicellular organisms from the three domains of life. The intein self-excises following translation of the host gene, and therefore incurs a fitness cost for its carrier. The symbiotic state of the intein to its host is dependent on the presence or absence of a homing endonuclease domain, which facilitates horizontal transfer of the molecule. Identification of this domain provides information on the evolutionary history of the intein, as well as patterns of horizontal gene transfer in microbial communities. I have therefore developed Hidden Markov Models (HMMs) to identify homing endonuclease domains …

Desert Hedgehog Is A Mammal-Specific Gene Expressed During Testicular And Ovarian Development In A Marsupial, William A. O'Hara

Master's Theses

Desert hedgehog (DHH) belongs to the hedgehog gene family that act as secreted intercellular signal transducers. DHH is an essential morphogen for normal testicular development and function in both mice and humans but is not present in the avian lineage. Like other hedgehog proteins, DHH signals through the patched (PTCH) receptors 1 and 2. Here we examine the expression and protein distribution of DHH, PTCH1 and PTCH2 in the developing testes of a marsupial mammal (the tammar wallaby) to determine whether DHH signalling is a conserved factor in gonadal development in all therian mammals.