Mechanisms of drug resistance inv-src transformed rat fibroblasts.

Persistent Link:
http://hdl.handle.net/10150/185090
Title:
Mechanisms of drug resistance inv-src transformed rat fibroblasts.
Author:
Lin, Ti.
Issue Date:
1990
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The central question of my dissertation is does cellular transformation increase the occurrence of gene amplification. I used a model system in which cellular transformation could be controlled by shifting the temperature. Rat-1 was the parental cell line and was not transformed at any temperature. The LA24 cell line carries an avian sarcoma virus with a temperature sensitive mutation in the v-src gene. These cells are transformed at 35°C, but become nontransformed at 40°C. Measurements of cell transformation included (1) growth on plastic, (2) growth in soft agar and (3) v-src RNA and protein expression. My first experiments were to examine the frequency and mechanisms of MTX and colchicine resistant variants. The frequency in generating MTX resistant clones was the same in transformed and nontransformed LA24 cells. However, dihydrofolate reductase gene amplification was the preferred mechanism of MTX resistance in transformed LA24 clones. The frequency in generating colchicine resistant clones was no different in transformed and nontransformed LA24 cells. P-glycoprotein gene amplification was also the preferred mechanism of colchicine resistance in transformed LA24 clones. To directly study the mutation rate of colchicine resistant variants on transformed and nontransformed LA24 cells, Luria-Delbruck fluctuation analysis was performed. Colchicine resistant variants were derived from a single cell that were grown to a population size of 10⁵ cells; they were then selected with colchicine. The data showed no increase in the mutation rate of transformed LA24 cells compared to untransformed cells upon selection in colchicine. In summary, I have shown that v-src transformation in Rat-1 fibroblasts causes a high frequency of P-glycoprotein gene amplification when selected with colchicine, and a high frequency of dihydrofolate reductase gene amplification when selected with MTX. Even though gene amplification is enhanced by v-src transformation, the frequency of generating colchicine and MTX variants is not related to cellular transformation state.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Biology
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Microbiology and Immunology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Trent, Jeffrey M.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleMechanisms of drug resistance inv-src transformed rat fibroblasts.en_US
dc.creatorLin, Ti.en_US
dc.contributor.authorLin, Ti.en_US
dc.date.issued1990en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe central question of my dissertation is does cellular transformation increase the occurrence of gene amplification. I used a model system in which cellular transformation could be controlled by shifting the temperature. Rat-1 was the parental cell line and was not transformed at any temperature. The LA24 cell line carries an avian sarcoma virus with a temperature sensitive mutation in the v-src gene. These cells are transformed at 35°C, but become nontransformed at 40°C. Measurements of cell transformation included (1) growth on plastic, (2) growth in soft agar and (3) v-src RNA and protein expression. My first experiments were to examine the frequency and mechanisms of MTX and colchicine resistant variants. The frequency in generating MTX resistant clones was the same in transformed and nontransformed LA24 cells. However, dihydrofolate reductase gene amplification was the preferred mechanism of MTX resistance in transformed LA24 clones. The frequency in generating colchicine resistant clones was no different in transformed and nontransformed LA24 cells. P-glycoprotein gene amplification was also the preferred mechanism of colchicine resistance in transformed LA24 clones. To directly study the mutation rate of colchicine resistant variants on transformed and nontransformed LA24 cells, Luria-Delbruck fluctuation analysis was performed. Colchicine resistant variants were derived from a single cell that were grown to a population size of 10⁵ cells; they were then selected with colchicine. The data showed no increase in the mutation rate of transformed LA24 cells compared to untransformed cells upon selection in colchicine. In summary, I have shown that v-src transformation in Rat-1 fibroblasts causes a high frequency of P-glycoprotein gene amplification when selected with colchicine, and a high frequency of dihydrofolate reductase gene amplification when selected with MTX. Even though gene amplification is enhanced by v-src transformation, the frequency of generating colchicine and MTX variants is not related to cellular transformation state.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectBiologyen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMicrobiology and Immunologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorTrent, Jeffrey M.en_US
dc.contributor.committeememberBernstein, Harrisen_US
dc.contributor.committeememberCress, Anne E.en_US
dc.contributor.committeememberWard, Oscar G.en_US
dc.contributor.committeememberDavis, John R.en_US
dc.identifier.proquest9028163en_US
dc.identifier.oclc708269088en_US
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