Life Sciences Commons^™

The Splice Is Not Right: Splice-Site-Creating Mutations In Cancer Genomes, Reyka Glencora Jayasinghe

Arts & Sciences Electronic Theses and Dissertations

Accurate interpretation of cancer mutations in individual tumors is a prerequisite for precision medicine. Large-scale sequencing studies, such as The Cancer Genome Atlas (TCGA) project, have worked to address the functional consequences of genomic mutations, with the larger goal of determining the underlying mechanisms of cancer initiation and progression. Many studies have focused on characterizing non-synonymous somatic mutations that alter amino acid sequence, as well as splice disrupting mutations at splice donors and acceptors. Current annotation methods typically classify mutations as disruptors of splicing if they fall on the consensus intronic dinucleotide splice donor, GT, the splice acceptor, AG. Splice …

Protein Structure-Guided Approaches To Identify Functional Mutations In Cancer, Sohini Sengupta

Arts & Sciences Electronic Theses and Dissertations

Distinguishing driver mutations from passenger mutations within tumor cells continues to be a major challenge in cancer genomics. Many computational tools have been developed to address this challenge; however, they rely heavily on primary protein sequence context and frequency/mutation rate. Rare driver mutations not found in many cancer patients may be missed with these traditional approaches. Additionally, the structural context of mutations on tertiary/quaternary protein structures is not taken into account and may play a more prominent role in determining phenotype and function. This dissertation first presents a novel computational tool called HotSpot3D, which identifies regions of protein structures that …

Sequence Analysis Methods For The Design Of Cancer Vaccines That Target Tumor-Specific Mutant Antigens (Neoantigens), Jasreet Hundal

Arts & Sciences Electronic Theses and Dissertations

The human adaptive immune system is programmed to distinguish between self and non-self proteins and if trained to recognize markers unique to a cancer, it may be possible to stimulate the selective destruction of cancer cells. Therapeutic cancer vaccines aim to boost the immune system by selectively increasing the population of T cells specifically targeted to the tumor-unique antigens, thereby initiating cancer cell death.. In the past, this approach has primarily focused on targeted selection of ‘shared’ tumor antigens, found across many patients. The advent of massively parallel sequencing and specialized analytical approaches has enabled more efficient characterization of tumor-specific …

Mechanistic Characterization Of Resistome And Microbiome Dynamics Across Diverse Microbial Habitats, Andrew John Gasparrini

Arts & Sciences Electronic Theses and Dissertations

Increasing antibiotic resistance in pathogens is a serious public health challenge, with over two million antibiotic resistant infections in the United States leading to at least 23,000 deaths and an estimated $55 billion in excess healthcare and societal costs. Antibiotic resistance has risen steadily in both pathogenic and benign bacteria since antibiotics’ introduction to agriculture and medicine 70 years ago. A dramatic reduction in the number of antibiotics approved for human use has accompanied this rise in antibiotic resistance, leading to the alarming prospect of a post-antibiotic era. Understanding the evolutionary origins, genetic contexts, and molecular mechanisms of antibiotic resistance …

Genetic Basis Of Thermal Divergence In Saccharomyces Species, Xueying C. Li

Arts & Sciences Electronic Theses and Dissertations

The genetic architecture of phenotypic divergence is a central question in evolutionary biology. Genetic architecture is impacted by whether evolution occurs through accumulation of many small-effect or a few large-effect changes, the relative contribution of coding and cis-regulatory changes, and the prevalence of epistatic effects. Our empirical understanding of the genetic basis of evolutionary change remains incomplete, largely because reproductive barriers limit genetic analysis to those phenotypes that distinguish closely related species. In this dissertation, I use hybrid genetic analysis to examine the basis of thermal divergence between two post-zygotically isolated species, Saccharomyces cerevisiae and S. uvarum. S. cerevisiae is …

A Tail Of Two Pancancer Projects: Somatic Variant Identification And Driver Gene Discovery Using Tcga, Matthew Hawkins Bailey

Arts & Sciences Electronic Theses and Dissertations

The implementation of next-generation genomic sequencing has exploded over the past dozen years. Large consortia, such as The Cancer Genome Atlas (TCGA); the International Cancer Genetics Consortium (ICGC); and the Pediatric Cancer Genome Projects (PCGP), made great strides in democratizing big data for the scientific community. These data sets provide a rich resource to build tools for somatic variant discovery and exploratory analysis. Public repositories hold the answer to many novel biological and clinical revelations i.e., the discovery of complex indels, splice creating mutations, alternative super enhancer binding sites, machine learning models to predict mutation impact, and cancer subtype classification …

A Mechanism Of Antimicrobial Resistance And A Mitigation Strategy, Christopher Bulow

Arts & Sciences Electronic Theses and Dissertations

ABSTRACT OF THE DISSERTATION

A Mechanism of Antimicrobial Resistance and a Mitigation Strategy

by

Christopher Bulow

Doctor of Philosophy in Biology and Biomedical Sciences

Molecular Genetics and Genomics

Washington University in St. Louis, 2018

Professor Gautam Dantas, Chair

The ability to treat infections, perform surgery, and administer immunosuppressants and chemotherapy depends on effective antibiotics. The emergence and spread of antimicrobial resistance is far outpacing the development of new therapies1-3 threatening to thrust medicine into a post-antibiotic era4. Many mechanisms of antimicrobial action and of antimicrobial resistance remain poorly understood as drug development struggles to keep pace. As resistance develops, the …

Methods To Record Transcription Factor Binding And Enhancer Activity Throughout Cellular Differentiation, Zongtai Qi

Arts & Sciences Electronic Theses and Dissertations

The ability to create distinct cell types is fundamental for the development of multicellular organisms. Since all cells in an organism contain the same genes, cellular diversity is achieved through the transcriptional network where transcription factors (TFs) interacts with cis-regulatory elements, leading to the selective transcription of different sets of genes. To better understand the functions of TFs and regulatory elements underlying cell fate decisions, we developed methods that are able to record their activities throughout cellular differentiation. In Chapter 2, we developed a degradation domain based induction system for ҃alling CardsӠmethod which maps the binding sites of TFs using …

Integration Of Local And Regional Regulatory Information In The Human Genome, Hemangi Govind Chaudhari

Arts & Sciences Electronic Theses and Dissertations

Gene regulation involves the integration of different sources of information at multiple levels. The action of transcription factors is integrated at cis-regulatory sequences (CRSs). Information from many CRSs is combined to drive spatiotemporally regulated gene expression. Prediction of CRS activity from DNA sequence is challenging because most occurrences of transcription factor binding sites (TFBS) are not functional. I assayed the activity of thousands of genomic sequences with Activator Protein 1 (AP-1) binding sites in K562 cells to identify features in flanking sequences that distinguish functional from non-functional TFBS. I find that sequence features directly adjacent to the AP-1 core motif, …

Multi-Omics Portraits Of Cancer, Kuan-Lin Huang

Arts & Sciences Electronic Theses and Dissertations

Precision oncology demands accurate portrayal of a disease at all molecular levels. However, current large-scale studies of omics are often isolated by data types. I have been developing computational tools to conduct integrative analyses of omics data, identifying unique molecular etiology in each tumor. Particularly, this dissertation presents the following contributions to the computational omics of cancer: (1) uncovering the predisposition landscape in 33 cancers and how germline genome collaborates with somatic alterations in oncogenesis; (2) pioneering methods to combine genomic and proteomic data to identify treatment opportunities; and (3) revealing selective phosphorylation of kinase-substrate pairs. These findings advance our …

Discerning Drivers Of Cancer: Computational Approaches To Somatic Exome Sequencing Data, Runjun Kumar

Arts & Sciences Electronic Theses and Dissertations

Paired tumor-normal sequencing of thousands of patient’s exomes has revealed millions of somatic mutations, but functional characterization and clinical decision making are stymied because biologically neutral ‘passenger’ mutations greatly outnumber pathogenic ‘driver’ mutations. Since most mutations will return negative results if tested, conventional resource-intensive experiments are reserved for mutations which are observed in multiple patients or rarer mutations found in well-established cancer genes. Most mutations are therefore never tested, diminishing the potential to discover new mechanisms of cancer development and treatment opportunities. Computational methods that reliably prioritize mutations for testing would greatly increase the translation of sequencing results to clinical …

Defining Neuronal Identity Using Microrna-Mediated Reprogramming, Matthew James Mccoy

Arts & Sciences Electronic Theses and Dissertations

Cell fate reprogramming is transforming our understanding of the establishment and maintenance of cellular identity. In addition, reprogramming holds great promise to model diseases affecting cell types that are prohibitively difficult to study, such as human neurons. Overexpression of the brain-enriched microRNAs (miRNAs), miR-9/9* and miR-124 (miR-9/9*-124) results in reprogramming human somatic cells into neurons and has recently been used to generate specific neuronal subtypes affected in neurodegenerative disorders. However, the mechanisms governing the ability of miR-9/9*-124 to generate alternative subtypes of neurons remained unknown. In this thesis, I report that overexpressing miR-9/9*-124 triggers reconfiguration of chromatin accessibility, DNA methylation, …

Discovering Rare Hematopoietic Clones Harboring Leukemia-Associated Mutations Using Error-Corrected Sequencing, Andrew Lee Young

Arts & Sciences Electronic Theses and Dissertations

Cancer is a heterogeneous group of diseases that currently takes over half a million lives per year in the United States alone. Our understanding of cancer has improved dramatically over the last forty years, beginning with the discovery that cancer is a disease of the genome. Currently, the set of somatic mutations found in malignancy are largely known. The specific somatic mutations driving an individual’s disease can be readily assessed at clinical presentation. Additionally, the functional consequences for many of these mutations are known as well as their role in tumorigenesis. Despite this understanding, a cure for cancer remains elusive. …