Publication Date


Document Type


First Advisor

Bode, Barrie P.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences


Recombinant DNA plasmids are often used to mediate forced gene overexpression or suppression in mammalian cells, to address questions regarding the role of specific proteins in cell behavior and function. To select for cells harboring such recombinant plasmids, lethal antibiotics such as Puromycin, Geneticin (Neomycin) and Zeocin are frequently used, as plasmids contain selective antibiotic resistance genes that biochemically disarm them. Antibiotic resistance, induced by plasmid-borne genes and chronic exposure to lethal antibiotics can likewise potentially change the phenotype of cells, confounding the conclusions drawn from experiments on gene overexpression or suppression. Yet, little is known about the effects of antibiotic resistance on cellular behavior and phenotype. In this study, we examined the impact of three commonly used antibiotics, Puromycin, Geneticin (Neomycin) and Zeocin on a rat liver epithelial cell line (RLE-Φ13), which is a liver progenitor cell type with stem cell-like properties, and is frequently used in our lab to examine the effects of forced overexpression of amino acid transporters on cell behavior. The data suggest that all three antibiotics induce a more aggressive growth phenotype in the RLE cells stably transfected with cognate plasmids conferring antibiotic resistance, relative to parent lines. However, a transition to a more mesenchymal phenotype and enhanced drug resistance do not seem to be outcomes of antibiotic resistance. Such antibiotic resistance-induced changes in cellular growth need to be considered when assessing the effects of amino acid transporter expression on cell function or metabolism.


45 pages




Northern Illinois University

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