X-Ray induced DNA damage – why use plants?
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1
Faculty of Medicine, University of Oslo, Norway
The comet assay was used to monitor DNA repair after X-ray exposures caused by 0.2-15 Gy. A clear distinction in the time course of DNA repair after 2 Gy was observed with an early ‘rapid phase’, lasting 20-40 minutes, being followed by a ‘slow phase’ which actually consists of a period of negligible repair and then rapid repair during 140-160 minutes. The fact that homozygous mutants for both ATM and BRCA1 fail to repair DNA completely during 3 hours after 2 Gy exposures indicates that repair processes occurring during the ‘slow phase’ involve ds breaks in DNA. Both BRCA1 and Rad51 expression are strongly upregulated by X-rays in Arabidopsis. Rye grass, Norway spruce and Sawara cypress also have ‘slow phase’ repair similar to Arabidopsis, suggesting that the requisite enzymes have to be induced in these plants as well. To look at the effect of genome size in relation to sensitivity to DNA damage, we exposed isolated nuclei from Norway spruce (19.2 Gbp genome), celery (14.1 Gbp), spinach (12.6 Gbp) Sawara cypress (8.9 Gbp), lettuce (2.6 Gbp) and Arabidopsis (0.135 Gbp) to X-rays. After a 1 Gy exposure, a linear relationship was seen between % tails and genome size, confirming the idea that larger genomes are more sensitive to X-ray damage.
Keywords:
X-Rays,
DS-breaks,
Arabidopsis slow phase repair,
Rye grass,
Norway spruce,
Genome Size
Conference:
ICAW 2015 - 11th International Comet Assay Workshop, Antwerpen, Belgium, 1 Sep - 4 Sep, 2015.
Presentation Type:
Oral Presentation
Topic:
Ecogenotoxicology
Citation:
Einset
JW and
Collins
A
(2015). X-Ray induced DNA damage – why use plants?.
Front. Genet.
Conference Abstract:
ICAW 2015 - 11th International Comet Assay Workshop.
doi: 10.3389/conf.fgene.2015.01.00062
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Received:
20 May 2015;
Published Online:
23 Jun 2015.
*
Correspondence:
Prof. John W Einset, Faculty of Medicine, University of Oslo, Oslo, Norway, john.einset@nmbu.no