After 30 years of research, p53 is recognized as one of the most frequently mutated genes in human cancer (Baker et al, 1989; Nigro et al, 1989; Momand et al, 2000; Daujat et la, 2001). To accomplish its tumor suppressive role, p53 transcriptionally regulates a multitude of genes involved in cell cycle progression, genomic stability, cellular senescence, apoptosis, angiogenesis, cell migration, and autophagy. To date approximately 150 genes are documented as direct p53 target genes. The goal of this dissertation research was to identify novel p53 family transcriptional targets and determine their functions in biologically-relevant processes downstream of the p53 family signaling axis.
In Chapter III of this dissertation, I describe the use of statistical and bioinformatic tools to perform genomic analyses and identify a subset of novel putative p53 transcriptional targets. With the overlay of genomic datasets and predictive mathematical models, I developed a panel of high-confidence p53 transcriptional targets. I describe current and future plans to analyze these target genes, in a high-throughput manner, and identify the contribution of each target gene to p53-regulated processes such as cell cycle arrest, apoptosis, and autophagy, among others.
In Chapter IV of this dissertation, I describe the identification of ISG20L1 as a target gene of p53 as well as family members p63 and p73. Ectopic expression of ISG20L1 decreased clonogenic survival, but changes in ISG20L1 protein levels did not alter apoptosis. Thus, we investigated the role of ISG20L1 in autophagy, a process commonly associated with type II cell death, and found that ISG20L1 knockdown decreased levels of autophagic vacuoles and LC3-II after genotoxic stress as assessed by electron microscopy, biochemical and immunohistochemical measurements of LC3-II.
Investigation of genes and signaling pathways involved in cell death associated with autophagy is critical given the keen interest in targeting autophagy as an anticancer therapeutic approach in tumor cells that are defective in apoptosis.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-05242010-175410 |
| Date | 16 June 2010 |
| Creators | Eby, Kathryn Grace |
| Contributors | Bruce Carter, Jennifer Pietenpol, Scott Hiebert, Larry Marnett, Sandra Zinkel |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu//available/etd-05242010-175410/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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