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Full-Text Articles in Medicine and Health Sciences

Exploiting Dna Repair And Er Stress Response Pathways To Induce Apoptosis In Glioblastoma Multiforme: A Dissertation, Jessica L. Weatherbee Aug 2016

Exploiting Dna Repair And Er Stress Response Pathways To Induce Apoptosis In Glioblastoma Multiforme: A Dissertation, Jessica L. Weatherbee

GSBS Dissertations and Theses

Glioblastoma multiforme (GBM) is a deadly grade IV brain tumor characterized by a heterogeneous population of cells that are drug resistant, aggressive, and infiltrative. The current standard of care, which has not changed in over a decade, only provides GBM patients with 12-14 months survival post diagnosis. We asked if the addition of a novel endoplasmic reticulum (ER) stress inducing agent, JLK1486, to the standard chemotherapy, temozolomide (TMZ), which induces DNA double strand breaks (DSBs), would enhance TMZ’s efficacy. Because GBMs rely on the ER to mitigate their hypoxic environment and DNA repair to fix TMZ induced DSBs, we ...


The Cellular Consequences Of Fus/Tls Depletion: A Loss Of Function Model For Amyotrophic Lateral Sclerosis: A Dissertation, Catherine L. Ward Jul 2014

The Cellular Consequences Of Fus/Tls Depletion: A Loss Of Function Model For Amyotrophic Lateral Sclerosis: A Dissertation, Catherine L. Ward

GSBS Dissertations and Theses

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the death of motor neurons, generally leading to paralysis and death within 3-5 years of onset. Over 50 different mutations in the gene encoding FUS/TLS (or FUS) will result in ALS, accounting for ~4% of all inherited cases. FUS is a multifunctional protein with important functions in DNA/RNA processing and stress response. How these mutations affect the structure or function of FUS protein and ultimately cause ALS is not known. The fact that mutations cause the protein to mislocalize from the nucleus to the cytoplasm of cells ...


Fus/Tls In Stress Response - Implications For Amyotrophic Lateral Sclerosis: A Dissertation, Reddy Ranjith Kumar Sama Mar 2014

Fus/Tls In Stress Response - Implications For Amyotrophic Lateral Sclerosis: A Dissertation, Reddy Ranjith Kumar Sama

GSBS Dissertations and Theses

Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease is a fatal neurodegenerative disease. ALS is typically adult onset and is characterized by rapidly progressive loss of both upper and lower motor neurons that leads to death usually within 3-5 years. About 90% of all the cases are sporadic with no family history while the remaining 10% are familial cases with mutations in several genes including SOD1, FUS/TLS, TDP43 and C9ORF72.

FUS/TLS (Fused in Sarcoma/Translocated in Liposarcoma or FUS) is an RNA/DNA binding protein that is involved in multiple cellular functions including DNA damage ...


Mdm2-P53 Signaling In Tissue Homeostasis And The Dna Damage Response: A Dissertation, Hugh S. Gannon Jun 2012

Mdm2-P53 Signaling In Tissue Homeostasis And The Dna Damage Response: A Dissertation, Hugh S. Gannon

GSBS Dissertations and Theses

The p53 transcription factor responds to various cellular stressors by regulating the expression of numerous target genes involved in cellular processes such as cell cycle arrest, apoptosis, and senescence. As these downstream pathways are harmful to the growth and development of normal cells when prolonged or deregulated, p53 activity needs to be under tight regulatory control. The Mdm2 oncoprotein is the chief negative regulator of p53, and many mouse models have demonstrated that absence of Mdm2 expression leads to constitutive p53 activation in a variety of cell types. While unregulated p53 can be deleterious to cells, functional p53 is essential ...


The Role Of Pc4 In Oxidative Stress: A Dissertation, Lijian Yu Jun 2011

The Role Of Pc4 In Oxidative Stress: A Dissertation, Lijian Yu

GSBS Dissertations and Theses

Oxidative stress is a cellular condition where cells are challenged by elevated levels of reactive oxygen species (ROS) that are produced endogenously or exogenously. ROS can damage vital cellular components, including lipid, protein, DNA and RNA. Oxidative damage to DNA often leads to cell death or mutagenesis, the underlying cause of various human disease states. Previously our laboratory discovered that human PC4 gene can prevent oxidative mutagenesis in the bacterium Escherichia coli and that the yeast homolog SUB1 has a conserved function in oxidation protection. In this thesis I examined the underlying mechanisms of PC4’s oxidation protection function. My ...


Regulation Of Wrn Function By Acetylation And Sirt1-Mediated Deacetylation In Response To Dna Damage: A Dissertation, Kai Li Jun 2010

Regulation Of Wrn Function By Acetylation And Sirt1-Mediated Deacetylation In Response To Dna Damage: A Dissertation, Kai Li

GSBS Dissertations and Theses

Werner syndrome (WS) is an autosomal recessive disorder associated with premature aging and cancer predisposition. WS cells show increased genomic instability and are hypersensitive to DNA-damaging agents. WS is caused by mutations of the WRN gene. WRN protein is a member of RecQ DNA helicase family. In addition to a conserved 3’–5’ helicase activity, the WRN protein contains unique 3’–5’ exonuclease activity. WRN recognizes specific DNA structures as substrates that are intermediates of DNA metabolism. WRN physically and functionally interacts with many other proteins that function in telomere maintenance, DNA replication, and DNA repair. The function of WRN ...


Defining The Roles Of P300/Cbp (Creb Binding Protein) And S5a In P53 Polyubiquitination, Degradation And Dna Damage Responses: A Dissertation, Dingding Shi Jan 2010

Defining The Roles Of P300/Cbp (Creb Binding Protein) And S5a In P53 Polyubiquitination, Degradation And Dna Damage Responses: A Dissertation, Dingding Shi

GSBS Dissertations and Theses

p53, known as the “guardian of the genome”, is the most well-characterized tumor suppressor gene. The central role of p53 is to prevent genome instability. p53 is the central node in an incredibly elaborate genome defense network for receiving various input stress signals and controlling diverse cellular responses. The final output of this network is determined not only by the p53 protein itself, but also by other p53 cooperating proteins.

p300 and CBP (CREB-Binding Protein) act as multifunctional regulators of p53 via acetylase and ubiquitin ligase activities. Prior work in vitro has shown that the N-terminal 595 aa of p300 ...


Regulation Of Dna Replication Origins In Fission Yeast: A Dissertation, Naveen Kommajosyula Aug 2009

Regulation Of Dna Replication Origins In Fission Yeast: A Dissertation, Naveen Kommajosyula

GSBS Dissertations and Theses

Cells need to complete DNA replication in a timely and error-free manner. To ensure that replication is completed efficiently and in a finite amount of time, cells regulate origin firing. To prevent any errors from being transmitted to the next generation, cells have the checkpoint mechanism.

The S-phase DNA damage slows replication to allow the cell to repair the damage. The mechanism of replication slowing by the checkpoint was not clear in fission yeast, Schizosaccharomyces pombe, at the start of my thesis. The downstream targets of the DNA damage checkpoint in fission yeast were also unclear. I worked on identifying ...


Checkpoint Regulation Of Replication Forks In Response To Dna Damage: A Dissertation, Nicholas Adrian Willis May 2009

Checkpoint Regulation Of Replication Forks In Response To Dna Damage: A Dissertation, Nicholas Adrian Willis

GSBS Dissertations and Theses

Faithful duplication and segregation of undamaged DNA is critical to the survival of all organisms and prevention of oncogenesis in multicellular organisms. To ensure inheritance of intact DNA, cells rely on checkpoints. Checkpoints alter cellular processes in the presence of DNA damage preventing cell cycle transitions until replication is completed or DNA damage is repaired.

Several checkpoints are specific to S-phase. The S-M replication checkpoint prevents mitosis in the presence of unreplicated DNA. Rather than outright halting replication, the S-phase DNA damage checkpoint slows replication in response to DNA damage. This checkpoint utilizes two general mechanisms to slow replication. First ...


The Role Of The Mrn Complex In The S-Phase Dna Damage Checkpoint: A Dissertation, Mary Elizabeth Porter-Goff Jan 2009

The Role Of The Mrn Complex In The S-Phase Dna Damage Checkpoint: A Dissertation, Mary Elizabeth Porter-Goff

GSBS Dissertations and Theses

The main focus of my work has been the role of the MRN in the S-phase DNA damage checkpoint. The MRN plays many roles in cellular metabolism; some are checkpoint dependent and some are checkpoint independent. The multiple roles in cellular metabolism complicate study of the role of the MRN in the checkpoint. MRN mutations in budding yeast and mammals may display separation of function. Mechanistically, MRN, along with its cofactor Ctp1, is involved in 5’ resection to create single stranded DNA that is required for both signaling and homologous recombination. However, it is unclear if resection is essential for ...


Dna Damage-Induced Apoptosis In The Presence And Absence Of The Tumor Suppressor P53: A Dissertation, Laura Michelle Mcnamee Oct 2008

Dna Damage-Induced Apoptosis In The Presence And Absence Of The Tumor Suppressor P53: A Dissertation, Laura Michelle Mcnamee

GSBS Dissertations and Theses

A key regulator of DNA damage-induced apoptosis is the tumor suppressor gene, p53. p53 is a transcription factor that upregulates genes involved in cell cycle arrest, apoptosis, and senescence. How p53 decides to activate one of these responses in response to DNA damage is largely unanswered. Many have hypothesized it is due to interaction with various signaling pathways and post-translational modification. The p53 tumor suppressor can be modified by SUMO-1 in mammalian cells, but the functional consequences of this modification are unclear. Conjugation to SUMO is a reversible post-translational modification that regulates several transcription factors involved in cell proliferation, differentiation ...


Roles For Histones H4 Serine 1 Phosphorylation In Dna Double Strand Break Repair And Chromatin Compaction: A Dissertation, Melissa Anne Foley Aug 2008

Roles For Histones H4 Serine 1 Phosphorylation In Dna Double Strand Break Repair And Chromatin Compaction: A Dissertation, Melissa Anne Foley

GSBS Dissertations and Theses

The study of DNA templated events is not complete without considering the chromatin environment. Histone modifications help to regulate gene expression, chromatin compaction and DNA replication. Because DNA damage repair must occur within the context of chromatin, many remodeling enzymes and histone modifications work in concert to enable access to the DNA and aid in restoration of chromatin after repair is complete. CK2 has recently been identified as a histone modifying enzyme. In this study we identify CK2 as a histone H3 tail kinase in vitro, identify the phospho-acceptor site in vitro, and characterize the modification in vivo in S ...


Mitotic Response To Dna Damage In Early Drosophila Embroyos: A Dissertation, Seongae Kwak Apr 2008

Mitotic Response To Dna Damage In Early Drosophila Embroyos: A Dissertation, Seongae Kwak

GSBS Dissertations and Theses

DNA damage induces mitotic exit delays through a process that requires the spindle assembly checkpoint (SAC), which blocks the metaphase to anaphase transition in the presence of unaligned chromosomes. Using time-lapse confocal microscopy in syncytial Drosophila embryos, we show that DNA damage leads to arrest during prometaphase and anaphase. In addition, functional GFP fusions to the SAC components MAD2 and Mps1, and the SAC target Cdc20 relocalize to kinetochore through anaphase arrest, and a null mad2mutation blocks damage induced prometaphase and anaphase arrest. We also show that the DNA damage signaling kinase Chk2 is required for damage induced metaphase ...


Characterization Of The Bach1 Helicase In The Dna Damage Response Pathway: A Dissertation, Rachel Litman Feb 2007

Characterization Of The Bach1 Helicase In The Dna Damage Response Pathway: A Dissertation, Rachel Litman

GSBS Dissertations and Theses

DNA damage response pathways are a complicated network of proteins that function to remove and/or reverse DNA damage. Following genetic insult, a signal cascade is generated, which alerts the cell to the presence of damaged DNA. Once recognized, the damage is either removed or the damaged region is excised, and the original genetic sequence is restored. However, when these pathways are defective the cell is unable to effectively mediate the DNA damage response and the damage persists unrepaired. Thus, the proteins that maintain the DNA damage response pathway are critical in preserving genomic stability.

One essential DNA repair protein ...


Epigenetic Telomere Protection By Drosophila Dna Damage Response Pathways: A Dissertation, Sarah R. Oikemus Sep 2006

Epigenetic Telomere Protection By Drosophila Dna Damage Response Pathways: A Dissertation, Sarah R. Oikemus

GSBS Dissertations and Theses

Several aspects of Drosophila telomere biology indicate that telomere protection can be regulated by an epigenetic mechanism. First, terminally deleted chromosomes can be stably inherited and do not induce damage responses such as apoptosis or cell cycle arrest. Second, the telomere protection proteins HP1 and HOAP localize normally to these chromosomes and protect them from fusions. Third, unprotected telomeres still contain HeT-A sequences at sites of fusions. Taken together these observations support a model in which an epigenetic mechanism mediated by DNA damage response proteins protects Drosophilatelomeres from fusion.

Work presented in this thesis demonstrates that the Drosophila proteins ...


Rb Inactivation Leads To E2f1-Mediated Dna Double Strand Break Accumulation: A Dissertation, Mary Theresa Pickering Apr 2006

Rb Inactivation Leads To E2f1-Mediated Dna Double Strand Break Accumulation: A Dissertation, Mary Theresa Pickering

GSBS Dissertations and Theses

Although it is unclear which cellular factor(s) is responsible for the genetic instability associated with initiating and sustaining cell transformation, it is known that most, if not all, cancers have mutations that inactivate the Rb-mediated growth control pathway. We show here that acute inactivation of Rb by RNA interference or expression of the E7 viral oncoprotein from human papillomavirus (HPV), and the resultant deregulation of one E2F family member, E2F1, leads to DNA double strand break (DSB) accumulation. These DSBs occur independent of apoptosis induction, and activation of ATM, NBS1, p53, or MAD2, and generation of reactive oxygen species ...


The Roles Of Dna Mismatch Repair And Recombination In Drug Resistance: A Dissertation, Melissa A. Calmann Dec 2004

The Roles Of Dna Mismatch Repair And Recombination In Drug Resistance: A Dissertation, Melissa A. Calmann

GSBS Dissertations and Theses

Cells have evolved different pathways in order to tolerate damage produced by different cytotoxic agents. Each agent reacts differently with DNA causing formation of different types of adducts, each eliciting the SOS stress response to induce different cellular repair pathways. One such type of substrate generated by cytotoxic agents is the DNA double strand break (DSB). The main pathway to repair such damage in the cell is through a process of recombination. In this thesis, I specifically examined the anti-cancer therapeutic agent cisplatin, which forms single- and double-strand breaks in DNA, and methylating agents, which are proposed to also be ...