Search for DNA interchange corresponding to sister chromatid exchanges in Chinese hamster ovary cells.
AUTOR(ES)
Loveday, K S
RESUMO
Chinese hamster ovary cells (CHO) grown for one cycle in bromodeoxyuridine (BrdU) contain a small amount (0.5%) of unusually dense double stranded DNA. This dense DNA has been previously interpreted as being bifilarly substituted with BrdU and hence evidence that sister chromatid exchange (SCE) formation proceeds via the Holliday model of recombination. However, the amount of this dense DNA is 100 times greater than that expected based on the SCE frequency in similarly cultured CHO cells, and it is not increased by treating the cells with mitomycin C. Moreover, contrary to expectations for bifilary substituted DNA, the amount of this dense DNA is not reduced by growing BrdU-labeled cells for a second cycle in TdR. Finally, DNA isolated from CHO cells contains a minor band (0.5%) with a density 0.025 gm/cc greater than that of the main band, whether or not BrdU has been incorporated. These results call into question the identification of this unusually dense DNA as bifilarly substituted and hence its previously postulated relationship to SCE formation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=342736Documentos Relacionados
- Multiple mechanisms generate extrachromosomal circular DNA in Chinese hamster ovary cells.
- Induction of Ouabain-resistant Mutation and Sister Chromatid Exchanges in Chinese Hamster Cells with Chemical Carcinogens Mediated by Human Pulmonary Macrophages
- Cytoplasmic requirement for peroxisome biogenesis in Chinese hamster ovary cells.
- Internalization of ricin in Chinese hamster ovary cells.
- Interchromosomal distribution of gamma ray-induced chromatid aberrations in Chinese hamster ovary cells
