Molecular Biology Commons^™

Preventing Thymus Involution In K5.Cyclin D1 Transgenic Mice Sustains The Naïve T Cell Compartment With Age, Michelle L. Bolner

Dissertations & Theses (Open Access)

The thymus maintains T cell receptor (TCR) repertoire diversity through perpetual release of self-MHC restricted naive T cells. However, thymus involution during the aging process reduces naïve T cell output, leading to defective immune responsiveness to newly encountered antigens. We have found that early thymus involution precipitates the age-associated shift favoring memory T cell dominancy in young control mice. Furthermore, we have shown that age-related thymus involution is prevented in mice expressing a keratin 5 promoter-driven Cyclin D1 (K5.D1) transgene in thymic epithelial cells (TECs). Thymopoiesis occurs normally in K5.D1 transgenic thymi and sustains T cell output to prevent the …

Molecular Regulation Of Vascular Calcification In Murine Models Of Atherosclerosis, Shanshan Gao

Dissertations & Theses (Open Access)

Background: Calcification occurs often in the atherosclerotic lesions of patients with coronary heart disease and animals with hypercholesterolemia, such as apolipoprotein-E deficient (ApoE-/-) mice. However, the mechanism(s) underlying the development of calcification in atherosclerosis remains unclear. ApoE acts as a lipid transporter, but also has been recognized as a potential regulator of osteogenesis. Little information is available as to whether ApoE has any direct impact on osteogenesis and calcification in vascular smooth muscle cells (VSMC). Several signal transduction pathways play a role in regulation of calcification, including the Wnt/β-catenin system and potentially GTAP, an ubiquitin-conjugating enzyme responsible for protein …

Histone H3 K4 Methylation Regulates The Spindle Assembly Checkpoint Through Direct Binding Of Multiple Checkpoint Components And Cdc20, Andria C. Schibler

Dissertations & Theses (Open Access)

Histone H3K4 methylation is conserved across species and is associated with active transcription. By using Saccharomyces cerevisiae, we found histone H3K4 methylation has a previously unknown role in regulating mitosis through the Spindle Assembly Checkpoint. The Spindle Assembly Checkpoint ensures duplicated chromosomes are segregated correctly and each daughter cell receives one full copy of the genome. Our data show SET1 mutants and histone H3K4 mutants display a resistance to the mitotic poison, benomyl. Moreover methylated histone H3 directly binds to Spindle Assembly Checkpoint proteins Bub3 and Mad2 as well as the activator of the Anaphase Promoting Complex (APC) protein …

Direct Regulation Of Apoptosis By Linear Ubiqutin Chain Assembly Complex (Lubac) And Feedback Regulation Of Lubac Function By Caspases, Donghyun Joo

Dissertations & Theses (Open Access)

Tumor Necrosis Factor-alpha (TNF-α) is a cytokine that plays a role in various cellular processes such as proliferation, differentiation (mainly through NF-κB signaling) and death (via apoptosis signaling). Recently, linear ubiquitination by LUBAC (linear ubiquitin chain assembly complex) was reported to have a regulatory function in TNF-α mediated NF-κB activation. Although LUBAC is suggested to control not only NF-kB signaling but also the apoptosis pathway, the precise mechanism of apoptosis regulation remains unknown. Moreover, NF-κB and apoptosis pathways have opposed but fundamental functions for various cellular processes. Although these two pathways actively interplay to balance the death and survival, the …

Prophylactic Cranial Irradiation Reduces The Incidence Of Brain Metastasis In A Mouse Model Of Metastatic Breast Cancer, Daniel L. Smith

Dissertations & Theses (Open Access)

Prophylactic cranial irradiation (PCI) is a preventative whole-brain irradiation technique used to reduce the incidence of brain metastasis and improve overall survival in select patients with small cell lung cancer and acute lymphoblastic leukemia. A population of breast cancer patients – stage IV, HER2+ or triple-negative – has emerged as having a high risk of developing brain metastases. Because only 10-20% of breast cancer patients diagnosed with brain metastases survive longer than one year, in this high-risk population the benefit of PCI – potential for reduced incidence of brain metastasis and improved overall survival – may outweigh the risks – …

Investigating The Interaction Of Aurka And Ube2c In Colorectal Cancer Cells, Apurva M. Hegde

Dissertations & Theses (Open Access)

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the US. Among the many genomic aberrations previously implicated in colorectal cancer, recurrent amplification of chromosome 20q is frequently associated with liver metastasis. Previous research in our lab identified a gene signature on chromosome 20q associated with colorectal cancer progression. In this study, one of the genes in the signature, the ubiquitin conjugating enzyme UBE2C, was identified through preliminary bioinformatics analysis as a candidate for further examination of its role in CRC progression. Co-expression analysis of UBE2C in tumor-normal datasets from the public database Oncomine revealed all the …

The Effect Of Activation Induced Cytidine Deaminase Phosphorylation And Herpes Virus Uracil Dna Glycosylase On Antibody Diversification, Marc Macaluso

Dissertations & Theses (Open Access)

Activation-induced cytidine deaminase (AID) is a mutagenic enzyme that is expressed in mammalian B-cells and initiates the antibody diversification processes of somatic hypermuntation (SHM) and isotype class switch recombination (CSR). AID is targeted to the immunoglobulin gene locus where it deaminates cytosines to generate uracil residues in DNA. This generates guanine-uracil (U:G) mismatch lesion which are recognized by uracil DNA glycosylase (UNG), a DNA repair enzyme that removes uracil from DNA and triggers downstream repair of the lesion. While UNG is a ubiquitously expressed DNA repair enzyme, its recognition and removal of AID introduced uracils is essential in both SHM …

Dna Polymerase Θ (Polq) And The Cellular Defense Against Dna Damage, Matthew J. Yousefzadeh

Dissertations & Theses (Open Access)

In mammalian cells, DNA polymerase θ (POLQ) is an unusual specialized DNA polymerase whose in vivo function is under active investigation. The protein is comprised of an N-terminal helicase-like domain, a C-terminal DNA polymerase domain, and a large central domain that spans between the two. This arrangement is also found in the Drosophila Mus308 protein, which helps confer resistance to DNA interstrand crosslinking agents. Homologs of POLQ and Mus308 are found in eukaryotes, including plants, but a comparison of phenotypes suggests that not all of these genes are functional orthologs. Flies with defective Mus308 are sensitive to DNA interstrand crosslinking …

Investigating The Roles Of P63 And P73 Isoforms To Therapeutically Treat P53-Altered Cancers, Avinashnarayan Venkatanarayan

Dissertations & Theses (Open Access)

Investigating the roles of p63 & p73 isoforms to therapeutically treat

p53-altered cancers

Avinashnarayan Venkatanarayan, M.S.

Supervisory Professor: Elsa R. Flores, Ph.D.

The TP53 tumor suppressor is mutated in approximately 50% of human cancers rendering cancer therapies ineffective. p53 reactivation suppresses tumor formation in mice. However, this strategy has proven difficult to implement therapeutically. An alternate approach to overcome p53 loss is to manipulate the p53-family members, p63 and p73, which interact and share structural similarities to p53. p63 and p73, unlike p53 are less frequently mutated and have two major isoforms with distinct functions …

Regulation Of Cell Adhesion By The Ferm Proteins, Ptpn14 And Merlin, Patty Dimarco Hewitt

Dissertations & Theses (Open Access)

Cell-cell adhesion is critical for the control of tissue organization and homeostasis. A family of proteins that regulate cell-cell adhesions is the FERM (4.1 protein, Ezrin, Radixin, Moesin) domain-containing proteins.One FERM domain protein, the non-receptor tyrosine phosphatase PTPN14, is mutated or deleted in several human cancers suggesting that it may be involved in tumor development and/or progression. Additionally, the loss of the FERM domain protein Merlin is associated with tumor development and metastasis.Both PTPN14 and Merlin have been shown to localize and possibly regulate adherens junction (AJ) functions. This work sought to determine if …

Measuring Single Cell Responses To Lapatinib In A Heterogeneous Population, Preety Priya

Dissertations & Theses (Open Access)

Cancer is notonedisease butasaga of diseases and is the outcome of disturbed homeostasis in the normal cells due to the deregulation of its genetic makeup. With advent of technologies thatallowdetailed molecular characterizationoftumors, targeted therapies have emerged as a more promising and specific mode of treatment. However, a major challenge with targeted therapy is the acquired resistance in the cancer cells to these therapies, quite often very rapidly in the course of a few months. One of the major targets in cancer has been the EGFR/ErbB2 network in breast and other cancer types. Prior work from our lab and others have …