Numerous chemical and physical agents can affect the structure of DNA and cause double-strand breaks, which may result in chromosome aberrations and the formation of micronuclei, which eventually leads to DNA loss. Nowadays, many studies on their genotoxicity are based on the scoring of micronuclei in plants. The application of a micronucleus test combined with fluorescence in situ hybridisation (FISH) permits the involvement of specific chromosomes or chromosome fragments in micronuclei formation to be determined. However, due to the dearth of FISH probes that can specifically target individual chromosomes in plants, until now the distribution of chromosome aberrations was usually based on using repetitive DNA such as centromeric, telomeric and rDNA sequences. Chromosome painting (CP), which permits the selective visualisation of entire chromosomes or their specific segments during both cell division and interphase, is one of the most advanced FISH-based approaches. In plants, CP is limited to several small-genome species, including the model grass Brachypodium distachyon (Brachypodium).
Here, we used multicolour FISH and CP to characterise the composition and to better understand the origin of the micronuclei that are induced in Brachypodium root-tip meristematic cells, which are caused by the application of chemical (maleic hydrazide) and physical (X-ray) mutagens. We show that this approach permits effective qualitative and quantitative analyses of the micronuclei and we attempted to use it to detect possible ‘hot spots’ for DNA breaks. We demonstrate that CP provides a significant improvement in the sensitivity of the ‘standard’ micronucleus test, which is commonly used in testing genotoxicity using plant cells. It appears that the application of mutagenic treatments to Brachypodium combined with its well-developed cytomolecular resources makes it a very promising, if not unique, model system for studying mutagenesis among all monocotyledonous plants.
This study was supported by the National Science Centre Poland (grant no. DEC-2012-04-A-NZ3-00572, DEC-2015-18-M-NZ2-00394).
Numerous chemical and physical agents can affect the structure of DNA and cause double-strand breaks, which may result in chromosome aberrations and the formation of micronuclei, which eventually leads to DNA loss. Nowadays, many studies on their genotoxicity are based on the scoring of micronuclei in plants. The application of a micronucleus test combined with fluorescence in situ hybridisation (FISH) permits the involvement of specific chromosomes or chromosome fragments in micronuclei formation to be determined. However, due to the dearth of FISH probes that can specifically target individual chromosomes in plants, until now the distribution of chromosome aberrations was usually based on using repetitive DNA such as centromeric, telomeric and rDNA sequences. Chromosome painting (CP), which permits the selective visualisation of entire chromosomes or their specific segments during both cell division and interphase, is one of the most advanced FISH-based approaches. In plants, CP is limited to several small-genome species, including the model grass Brachypodium distachyon (Brachypodium).
Here, we used multicolour FISH and CP to characterise the composition and to better understand the origin of the micronuclei that are induced in Brachypodium root-tip meristematic cells, which are caused by the application of chemical (maleic hydrazide) and physical (X-ray) mutagens. We show that this approach permits effective qualitative and quantitative analyses of the micronuclei and we attempted to use it to detect possible ...
2B7 - Building 2 GSA2018_APCC6 GSACC62018@canberra.edu.au
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