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Radiation-induced damages in single- and double-stranded DNA
V Isabelle1, C Prévost, M Spotheim-Maurizot
1Centre de Biophysique Moléculaire, CNRS, Orléans, France.
International Journal of Radiation Biology
|February 1, 1995
Summary
DNA strandedness impacts radiation-induced damage differently across sequences. While overall damage yields are similar, specific sequences like 5'-AATT show altered radiosensitivity based on DNA conformation (single vs. double-stranded).
Area of Science:
- Molecular Biology
- Radiation Biology
- Biophysics
Background:
- DNA damage from ionizing radiation is a critical area of study.
- Understanding DNA conformation's role in radiosensitivity is essential for predicting cellular responses.
Purpose of the Study:
- To investigate the influence of DNA strandedness (single vs. double) on radiation-induced DNA damage.
- To analyze the formation of frank strand breaks (FSB) and alkali-labile sites (ALS) in different DNA conformations.
Main Methods:
- Irradiation of single-stranded (ss-ss) and double-stranded (ds-ds) oligonucleotides using gamma-rays and fast neutrons.
- Sequencing gel electrophoresis to map DNA damage at nucleotide resolution.
- Analysis of damage in half single-half double stranded DNA (ss-ds and ds-ss).
Main Results:
- No significant differences in overall FSB and ALS yields between single and double-stranded DNA with random sequences.
- Increased alkaline lability observed at specific guanine sites within single-stranded regions of ss-ds and ds-ss DNA.
- The 5 andomIndex sequences exhibited reduced radiosensitivity in double-stranded DNA but not in single-stranded DNA.
Conclusions:
- DNA strandedness does not generally alter the yield of radiation-induced DNA strand breaks and alkali-labile sites.
- Specific DNA sequences, such as 5 andomIndex, display conformation-dependent radiosensitivity.
- DNA conformation plays a crucial role in the radiosensitivity of particular nucleotide sequences.