Insights into the mechanisms of sister chromatid exchange formation.
The DNA lesions responsible for the formation of sister chromatid exchanges (SCEs) have been the object of research for a long time. SCEs can be visualized by growing cells for either two rounds of replication in the presence of 5-bromo-2'-deoxyuridine (BrdU) or for one round with BrdU and the next without. If BrdU is added after cells were treated with a DNA-damaging agent, the effect on SCEs can only be analyzed in the second post-treatment mitosis. If one wishes to analyze the first post-treatment mitosis, cells unifilarily labeled with BrdU must be treated. Due to the highly reactive bromine atom, BrdU interacts with such agents like ionizing and UV radiation enhancing the frequency of SCEs. However, its precise role in this process was difficult to assess for a long time, because no alternative technique existed that allowed differential staining of chromatids. We have recently developed a method to differentially label sister chromatids with biotin-16-2'-deoxyuridine-5'-triphosphate (biotin-dUTP) circumventing the disadvantage of BrdU. This technique was applied to study the SCEs induced by ionizing and UV radiation as well as by mitomycin C, DNaseI and AluI. This article is a review of the results and conclusions of our previous studies.
Wojcik
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Institute of Nuclear Chemistry and Technology, Warszawa, Poland.
Bruckmann
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Obe
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D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives* / Q000494:pharmacology; D001973:Bromodeoxyuridine / Q000494:pharmacology / Q000633:toxicity; D016466:CHO Cells / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure; D007446:Chromosome Inversion; D002875:Chromosomes / Q000187:drug effects / Q000528:radiation effects*; D006224:Cricetinae; D003412:Cricetulus; D003432:Cross-Linking Reagents / Q000494:pharmacology / Q000633:toxicity; D004249:DNA Damage; D004261:DNA Replication; D003856:Deoxyuracil Nucleotides / Q000494:pharmacology; D005609:Free Radicals; D016193:G1 Phase; D006801:Humans; D016685:Mitomycin / Q000494:pharmacology / Q000633:toxicity; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology; D012854:Sister Chromatid Exchange / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D013194:Staining and Labeling; D014466:Ultraviolet Rays / Q000009:adverse effects; D014965:X-Rays / Q000009:adverse effects; D014544:Uridine Triphosphate / Q000031:analogs & derivatives
D001710:Biotin; D001973:Bromodeoxyuridine; D003432:Cross-Linking Reagents; D003856:Deoxyuracil Nucleotides; D005609:Free Radicals; D016685:Mitomycin; D011838:Radiation-Sensitizing Agents; C087624:biotin-16-dUTP; D014544:Uridine Triphosphate