Molecular Biology Commons^™

Practical Applications And Future Directions Of Genetic Code Expansion: Validation Of Novel Akt1 Substrates And The Design Of A Synthetic Auxotroph Strain Of B. Subtilis, Mcshane M. Mckenna

Electronic Thesis and Dissertation Repository

In Chapter 1, site-specifically phosphorylated variants of the oncogene Akt1 were made in Escherichia coli using the orthogonal translation system that enable genetic code expansion with phosphoserine. The differentially phosphorylated variants of Akt1 were used to validate newly predicted Akt1 substrates. The predicted target sites of the peptide substrates were synthesized and subjected to in vitro kinase assays to quantify the activity of each Akt1 phosphorylated variant towards the predicted peptide. A previously uncharacterized kinase-substrate interaction between Akt1 and a peptide derived from RAB11 Family Interacting Protein 2 (RAB11FIP2) was validated in vitro. Chapter 2 describes the preliminary development of …

Functional Investigation Of The Role Of The Retinoblastoma Protein In Genome Stability, Aren E. Marshall

Electronic Thesis and Dissertation Repository

Genome instability is an enabling characteristic of cancerous cells. It has recently been discovered that the retinoblastoma protein (pRB), typically known for its role in cell cycle regulation, also aids in the maintenance of genome stability. Intriguingly, mutations to the pRB gene, RB1, can arise late in tumorigenesis in cancer cells whose cell cycle regulation is already compromised by another mutation. This suggests that pRB’s functions in genome stability could underlie cancer relevant characteristics that are independent of its ability to negatively regulate proliferation. The overall aim of this thesis is to characterize the different means through which pRB …

Investigating E2f Independent Cell Cycle Control And Tumor Suppression By Prb, Michael J. Thwaites

Electronic Thesis and Dissertation Repository

Cellular division is primarily controlled at the G1 to S-phase transition of the cell cycle by the retinoblastoma tumor-suppressor protein (pRB). The ability of pRB to restrict S-phase entry is primarily attributed to the repression of E2F transcription factors required to upregulate cell cycle target genes necessary for cellular division. Interestingly, while pRB is disrupted in the vast majority of human cancers, mutations typically target upstream regulators of pRB leading to inactivation through hyperphosphorylation. The rarity of direct pRB mutations suggests that the regulation of the cell cycle by pRB may involve additional mechanisms outside of E2F repression, as this …

Comprehensive Molecular Characterization Of Human Nodal, Scott D. Findlay

Electronic Thesis and Dissertation Repository

Nodal and related ligands are highly conserved members of the TGF-beta superfamily with well-established and essential roles in the early embryonic development of vertebrates, and in cell fate decisions in human embryonic stem (hES) cells. Aberrant NODAL signaling also generally promotes pro-tumourigenic phenotypes and the progression of a wide array of human cancers. Despite being pursued as a potential therapeutic target, many aspects of NODAL’s molecular biology remain poorly understood. This thesis provides a comprehensive characterization of gene expression from the human NODAL locus at multiple levels. First, an intronic NODAL SNP known as rs2231947 was found to be functional …

Characterization Of The Catalytic Ck2 Subunits With Substitutions At Residues Involved In Inhibitor Binding, Paul Desormeaux

Electronic Thesis and Dissertation Repository

CK2 is a constitutively active, ubiquitously expressed and pleiotropic serine/threonine protein kinase that is implicated in many cellular functions including tumorigenesis. CK2 has two catalytic subunits, CK2a and CK2a’, that carry out its function in the cell. Previous studies have indicated that inhibitor-refractory mutants have been effective in recovering residual CK2 activity, in the presence of inhibitors, when compared to wild type CK2. Based on these observations, inhibitor-refractory mutants were created for both CK2a and CK2a’ and tested with various concentrations with two CK2-specific inhibitors, CX-4945 and inhibitor VIII. The CK2a triple mutant (V66A/I174A/H160D) was tested in inducible U2OS Flp-In …

Characterization Of Numb As A Regulator Of Anaplastic Lymphoma Kinase, Ran Wei

Electronic Thesis and Dissertation Repository

Cellular events rely on protein-protein interactions that are often mediated by modular domains which recognize particular sequence motifs in binding partners. The NUMB protein is the first described cell fate determinant and multifaceted adaptor that is involved in a wide variety of cellular events. NUMB mainly mediates protein interactions via its modular PTB domain. Here we present a systematic investigation of the NUMB-PTB interactome by employing an integrative strategy combining both protein and peptide arrays. We profiled NUMB-PTB binding specificity and interacting proteins genome-wide. The receptor tyrosine kinases (RTKs) are found highly enriched in the interactome, raising the possibility that …

Sirna Targeting Of Thymidylate Synthase, Thymidine Kinase 1 And Thymidine Kinase 2 As An Anticancer Therapy: A Combinatorial Rnai Approach, Christine Di Cresce

Electronic Thesis and Dissertation Repository

Thymidylate synthase (TS) is the only de novo source of thymidylate (dTMP) for DNA synthesis and repair. Drugs targeting TS protein are a mainstay in cancer treatment but off-target effects and toxicity limit their use. Cytosolic thymidine kinase (TK1) and mitochondrial thymidine kinase (TK2) contribute to an alternative dTMP-producing pathway, by salvaging thymidine from the tumour milieu, and may modulate resistance to TS-targeting drugs. We have previously shown that TS antisense molecules (oligodeoxynucleotides, ODNs, and small interfering siRNA, siRNA) sensitize tumour cells, both in vitro and in vivo, to TS targeting drugs. As both TS and TKs contribute to cellular …

Transcriptional Regulation By The Oncogenic Znf217/Corest Complex, Gobi Thillainadesan

Electronic Thesis and Dissertation Repository

The ZNF217 transcription factor is an oncogene found within the 20q13 amplicon and is amplified and overexpressed in many cancers including breast and ovarian. Overexpression of ZNF217 leads to increased cell proliferation, survival, and causes resistance to TGFβ's anti-proliferative effects.

ZNF217 is a core constituent of a transcriptional complex that includes CoREST, HDAC1/2, LSD1, and the CtBP1/2. In this study, I have combined genome-wide biochemical approaches to identify genes directly regulated by ZNF217. I have identified the tumor suppressor and cell cycle inhibitor, p15^ink4b, as a direct target of the ZNF217 complex and demonstrated that ZNF217 represses the …

Characterization Of A Tumour Suppressor Function Of Ranbpm, Elnaz Atabakhsh

Electronic Thesis and Dissertation Repository

Ran-binding protein M (RanBPM) is an evolutionarily conserved nucleocytosolic protein that has been proposed to regulate various cellular processes, including protein stability, gene expression, receptor-mediated signalling pathways, cell adhesion, development, and apoptosis. Despite the multitude of functions attributed to RanBPM however, little is known regarding the precise mechanisms by which RanBPM executes these cellular roles. In this work, we seek to address this matter by describing functions for RanBPM in the regulation of apoptotic and pro-survival signalling pathways, and in cellular transformation.

We first identify RanBPM as a pro-apoptotic protein that regulates the activation of the intrinsic apoptotic signalling pathway …