DNA damage.ppt
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There are five main types of endogenous DNA damage including oxidation of bases from reactive oxygen species, alkylation of bases such as methylation, and hydrolysis of bases through deamination, depurination, and depyrimidination. DNA can also be damaged through alkylation and oxidation by exogenous sources like radiation exposure. Various mutagens including base analogs, intercalating agents, and UV light-induced thymine dimers further contribute to DNA damage that must be repaired.
![Types of damage
There are five main types of damage to DNA due to endogenous cellular
processes:
oxidation of bases [e.g. 8-oxo-7,8-dihydroguanine (8-oxoG)] and generation of
DNA strand interruptions from reactive oxygen species,
alkylation of bases (usually methylation), such as formation of 7-
methylguanine, 1-methyladenine, 6-O-Methylguanine
hydrolysis of bases, such as deamination, depurination, and depyrimidination.](https://image.slidesharecdn.com/dnadamage-221005095702-82d15704/85/DNA-damage-ppt-1-320.jpg)
DNA damage.ppt
- 1. Types of damage There are five main types of damage to DNA due to endogenous cellular processes: oxidation of bases [e.g. 8-oxo-7,8-dihydroguanine (8-oxoG)] and generation of DNA strand interruptions from reactive oxygen species, alkylation of bases (usually methylation), such as formation of 7- methylguanine, 1-methyladenine, 6-O-Methylguanine hydrolysis of bases, such as deamination, depurination, and depyrimidination.
- 2. DNA UNDERGOES DAMAGE SPONTANEOUSLY FROM HYDROLYSIS(Ë®½â) AND DEAMINATION(È¥°±»ù) ? This is ironic since the proper structure of the double helix depends on an aqueous environment.
- 3. Deamination C-U Depurination ----> an abasic site Deamination of 5-mC---->T
- 4. DNA IS DAMAGED BY ALKYLATION, OXIDATION, AND RADIATION Often mispqir with thymine G:C ¨CA:T Reactive oxygen species O2-, H2O2, OH? G modification (alkylation & oxidation)
- 5. Thymine dimer by ultraviolet light Incapable of base-pairing and cause the DNA polymerse to stop during replication
- 6. Clastogenic ¨C ionizing radiation and agents like bleomycin that cause DNA to break are said to be clastogenic.
- 7. MUTATIONS ARE ALSO CAUSED BY BASE ANALOGS AND INTERCALATING AGENTS Base analogues
- 8. Intercalating agents which cause the deletion or addition of a base pair or a few base pairs
- 9. DNA DAMAGE DNA undergoes damage spontaneously from hydrolysis and deamination
- 10. DNA is damaged by alkylation, oxidation, and radiation
- 11. Thymine dimer caused by UV light
- 12. Base analogs and intercalating agents that cause mutations in DNA
- 13. Ames test for carcinogens
- 14. Bruce N. Ames Professor of the Graduate School Division of Biochemistry and Molecular Biology, UC Berkeley
- 15. REPAIR OF DNA DAMAGE