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Mutagenesis by simian virus 40. I. detection of mutations in Chinese hamster cell lines using different resistance
Abstract:
The mutagenic action of SV40 in permanent lines of Chinese hamster cells (CHO-K1 and V79) was investigated with the aid of different resistance markers. The markers studied had resistance to 8-azaguanine (25 and 30 mug/ml), aminopterin (3.3--5.5X10(-3) mug/ml), colchicine (6.5 and 7.0X10(-2) mug/ml) and 5-bromodeoxyuridine (50--120 mug/ml), respectively. After virus infection the mutation frequencies were increased by one (azaguanine, aminopterin) and two (colchicine) orders of magnitude as compared with spontaneous mutation frequencies. In contrast, it was not possible to enhance the frequency of mutation to BUdR resistance. On the other hand, the ability to proliferate in HAT medium was induced in three of five BUdR-resistant cell clones by infection with SV40. The resistance induced by SV40 was stable when isolated clones were cultured under non-selective conditions. Mechanisms are proposed that may be responsible for the mutagenic action of SV40.
Insights
Simian virus 40 (SV40) demonstrated mutagenic effects in Chinese hamster cells, increasing mutation frequencies for specific drug resistances. However, it did not increase resistance to 5-bromodeoxyuridine (BUdR) but could induce resistance in some BUdR-resistant cells.
Area of Science:
- * Virology
- * Molecular Biology
- * Cell Biology
Background:
- * Simian virus 40 (SV40) is a well-characterized DNA tumor virus with known oncogenic properties.
- * Understanding the mutagenic potential of viruses like SV40 is crucial for assessing their role in cellular transformation and disease.
- * Previous studies have explored the interaction of SV40 with host cell DNA and its effects on cellular processes.
Purpose of the Study:
- * To investigate the mutagenic action of SV40 in permanent Chinese hamster cell lines (CHO-K1 and V79).
- * To assess the frequency of mutations induced by SV40 using various drug resistance markers.
- * To explore the potential of SV40 to induce or alter drug resistance phenotypes in mammalian cells.
Main Methods:
- * Infection of Chinese hamster cells (CHO-K1 and V79) with SV40.
- * Measurement of mutation frequencies using resistance markers for 8-azaguanine, aminopterin, colchicine, and 5-bromodeoxyuridine (BUdR).
- * Culture of isolated resistant cell clones under non-selective conditions to assess stability of induced resistance.
Main Results:
- * SV40 infection significantly increased mutation frequencies for 8-azaguanine, aminopterin, and colchicine resistance by one to two orders of magnitude compared to spontaneous frequencies.
- * SV40 infection did not enhance the frequency of mutations conferring resistance to 5-bromodeoxyuridine (BUdR).
- * Infection with SV40 induced the ability to proliferate in HAT medium in three out of five BUdR-resistant cell clones, indicating induced resistance.
Conclusions:
- * SV40 exhibits mutagenic activity in Chinese hamster cells, particularly for certain drug resistance markers.
- * The virus's effect on BUdR resistance is complex, not directly increasing mutation frequency but capable of inducing resistance phenotypes.
- * The induced resistance to HAT medium by SV40 was stable, suggesting potential mechanisms for viral-mediated genetic alteration.