Related Experiment Videos
Spontaneous and ultraviolet-induced mutations on a single-stranded shuttle vector transfected into monkey cells
C Madzak1, J B Cabral-Neto, C F Menck
1Laboratory of Molecular Genetics, Institut de Recherches Scientifiques sur le Cancer, Villejuif, France.
Mutation Research
|August 1, 1992
Summary
Single-stranded DNA exhibits significantly higher mutation rates than double-stranded DNA, both spontaneously and after UV exposure. This study details the mutation types and locations, revealing insights into DNA repair mechanisms.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Shuttle vector plasmid PCF3A, containing the supF target gene, can be introduced into monkey COS7 cells.
- Previous research indicated single-stranded DNA (ssDNA) has lower survival and higher mutation frequency post-UV irradiation compared to double-stranded DNA (dsDNA).
Purpose of the Study:
- To investigate spontaneous and ultraviolet-induced mutagenesis using single-stranded PCF3A DNA.
- To analyze the sequence of mutant plasmids and characterize mutation types and locations.
Main Methods:
- Transfection of monkey COS7 cells with single-stranded and double-stranded PCF3A plasmid DNA.
- Sequence analysis of mutant plasmids to identify mutations.
- Comparison of mutation frequency, location, and base changes between ssDNA and dsDNA.
Main Results:
- Single-stranded DNA-derived plasmid progeny showed a 10-fold higher spontaneous mutation frequency than double-stranded DNA-derived progeny.
- Mutations in ssDNA targeted putative lesion sites with distinct base change patterns compared to dsDNA.
- Frameshift mutations and multiple mutations were more frequent in ssDNA, suggesting error-prone polymerization on a single-stranded template.
Conclusions:
- Single-stranded DNA is more susceptible to both spontaneous and UV-induced mutations.
- The nature and frequency of mutations differ significantly between single-stranded and double-stranded DNA templates.
- Error-prone polymerization may contribute to the high frequency of multiple mutations observed with single-stranded DNA.