Viral oncogenes in human fibroblasts.
Item
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Title
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Viral oncogenes in human fibroblasts.
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Identifier
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AAI9130364
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identifier
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9130364
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Creator
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Resnick-Silverman, Lois A.
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Contributor
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Adviser: Harvey L. Ozer
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Date
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1991
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Language
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English
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Publisher
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City University of New York.
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Subject
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Health Sciences, Immunology
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Abstract
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To clarify the role of SV40 T antigen in the transformation of human fibroblasts this laboratory has generated immortalized transformants (HAL) using origin-defective mutants of SV40 encoding a temperature sensitive large T antigen (tsA58). At the permissive temperature (35{dollar}\sp\circ{dollar}C) HAL cells have properties resembling those of cell lines transformed by wild type SV40. However at the restrictive temperature (39{dollar}\sp\circ{dollar}C) HAL cells are unable to proliferate or form colonies. T antigen binding to the cellular proteins Rb and p53 is reduced upon temperature shift up.;Although PyLT antigen is capable of immortalizing rat embryo fibroblast (REF) cells, transfection of human fibroblasts with PyLT does not result in extension of their lifespan or immortalization. Stable introduction of PyLT into HAL cells by retrovirus vector does not result in the rescue of any colonies at the restrictive temperature.;Whereas E1A 12S protein has been shown to immortalize REF cells and to rescue tsA58-transformed REF cells at the restrictive temperature, this is not the case in HAL cells. Transfection of a plasmid encoding the E1A 12S protein and the human HPRT gene into HAL cells results in colonies which express the 12S protein but are still temperature-sensitive. A rare clone, Ad-1, showed restored growth at 39{dollar}\sp\circ{dollar}C. These cells are not revertants of the tsA58 genome but the reasons for the extended viability of Ad-1 cells at 39{dollar}\sp\circ{dollar}C remain unknown. Immunoblots have shown that polyoma LT antigen or E1A can be immunoprecipitated with antiserum to Rb protein in these cell lines, demonstrating that the binding of Rb alone is insufficient for the rescue of HAL fibroblasts. These studies and those of others indicate that multiple cellular and viral functions are involved in SV40-mediated transformation and immortalization of human fibroblasts.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
