Date of Award

Spring 1-1-2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Jingshi Shen

Second Advisor

Greg Odorizzi

Third Advisor

Ding Xue

Fourth Advisor

Mark Winey

Fifth Advisor

Xuedong Liu

Abstract

Forward genetics in classic model organisms has been a key driving force for establishing the basic principles of cellular biology. However, many cellular pathways including membrane trafficking pathways are more complex in mammals, often exhibiting unique features not found in lower model organisms. To address this, I use a multi-pronged approach taking advantage of the haploid genetic system in human cells to explore these genetic features in a mammalian cell context. First, I direct a series of forward comparative genetic screens toward the dissection of a class of membrane bound molecules -the glycophosphatidylinositol-anchored proteins (GPI- APs). My findings demonstrate that, despite their similarity in overall architecture and subcellular localization, GPI-APs follow markedly distinct biosynthetic and trafficking pathways. Second, I developed a robust metric of cell viability: the Gene-trap Strand Profile (GSP). Using this metric I identified essential, semi-essential and redundant genes in HAP1 cells spanning virtually all gene groups. Last, I leverage the haploid genetic system toward the understanding of cell-cell interactions of the immune system, and explore how cancer cells escape cytotoxic lymphocyte mediated apoptosis. This study provides the first unbiased, systematic view of target cell genes involved in the recognition of tumor cells by NK cells, and will serve as a paradigm for understanding the interplay between innate immunity and tumorigenesis. Taken together, this work provides high-level views of mammalian-specific biology which were previously inaccessible with lower model organisms, and provides insight into the networks of genes regulating these fundamental cellular processes.

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