Correlation between repair patch ligation and nucleosome rearrangement in human cells treated with bleomycin, UV radiation or methyl methanesulfonate
- 1 January 1992
- journal article
- research article
- Published by Oxford University Press (OUP) in Carcinogenesis: Integrative Cancer Research
- Vol. 13 (1) , 135-138
- https://doi.org/10.1093/carcin/13.1.135
Abstract
We have examined ligation and nucleosome rearrangement of repair patches in chromatin of human fibroblasts damaged with bleomycin (BLM), UV radiation and methyl methanesulfonate (MMS) to follow completion of excision repair involving different combinations of repair enzymes. Conditions were used that allowed analysis of the correlation between these two events over a large range (i.e. from 5% to >99% ligated). Cells exposed to BLM were reversibly permeabilized with L-α-lysophosphatidylcholine and pulse-labeled with either [3H]dTTP or [3H]dThP to label selectively cells that ‘reseal their membranes’ at different rates. A striking difference is observed in the rates of ligation of these nascent repair patches, in that those labeled with [3H]dTTP are ligated much slower (25–50% unligated after 24h) than those labeled with [3H]dThd ( 0.8 in each case, indicating that these two features of nascent repair patches are 'moderately coupled' events. These results support the idea that ligation of repair patches is a prerequisite for nucleosome rearrangement following three different modes of excision repair.Keywords
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