Background
The spectrum of
ultraviolet light ranges from 100 to 400 nm and is divided into UV-A
(320-400 nm), UV-B (280-320 nm) and UV-C (<280 nm).The complete
spectrum is present in the natural sunlight, but only UV-A and -B reach
the earth's surface, while the latter one is completely absorbed by the
atmosphere and therefore doesn’t play any role for environmental
exposure. UV-B makes only a small fraction of the toal irradiation,
while UV-A is the predominat genotoxic exposure in the natural
environment. While UV-B is directly absorbed by biomacromolecules like
proteins and nucleic acids, UV-A causes indirect genotoxic and
cytotoxic effects via sensitizers. The absorbed energy is transfered to
oxygen and leads to formation of radical oxygen species (ROS). ROS are
responsible for a number of mutagenic lesion to the DNA.
8-Oxoguanine which mispaires with adenine and induces GC→AT transition is the most common DNA alteration. Besides 8-oxo-G numerous other damages are known to be induced by UV-A radiation, such as thymidine glycol and single strand breaks. For removing the damage from the genome there are two main repair mechanism:
To examine the influence of UV-light on DNA, cells are exposed to it under controlled conditions and afterwards analysed by specific assays.
We use the following standard assays to monitor genotoxic effects of UV-A irradiation:
Ongoing projects cover the determination of the damage spectrum including the distribution qualification, quantification as well as characterisation of the distribution of DNA damages induced by UV-A exposure.
These studies were performed in different skin cell lines as well as in reconstituted human skin.
8-Oxoguanine which mispaires with adenine and induces GC→AT transition is the most common DNA alteration. Besides 8-oxo-G numerous other damages are known to be induced by UV-A radiation, such as thymidine glycol and single strand breaks. For removing the damage from the genome there are two main repair mechanism:
To examine the influence of UV-light on DNA, cells are exposed to it under controlled conditions and afterwards analysed by specific assays.
We use the following standard assays to monitor genotoxic effects of UV-A irradiation:
- Comet-assay
- Cloning-assay
- Micronucleus-assay
- Live/Death staining
- Annexin
V staining
- immunofluorescence techniques
- live cell imaging of GFP tagged repair proteins
- RNA-array techniques
- Protein analysis
- Chromatin-IP
Ongoing projects cover the determination of the damage spectrum including the distribution qualification, quantification as well as characterisation of the distribution of DNA damages induced by UV-A exposure.
These studies were performed in different skin cell lines as well as in reconstituted human skin.
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Damage and Repair Topics |
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| DNA Damage Home |
DNA Double Strand Repair | Comet-assay
and Comet-FISH |
Intrinsic Oxidative |