Intermediates in excision repair by human cells: use of S1nuclease and benzoylated naphthoylated cellulose to reveal single-strand breaks

Biochemistry ◽  
1977 ◽  
Vol 16 (20) ◽  
pp. 4483-4490 ◽  
Author(s):  
Peter Karran ◽  
N. Patrick Higgins ◽  
Bernard Strauss
Keyword(s):  
Excision Repair ◽  
Human Cells ◽  
Single Strand ◽  
Strand Breaks ◽  
Single Strand Breaks

scholarly journals DNA DAMAGE AND REPAIR IN EUKARYOTIC CELLS

Genetics ◽  
1974 ◽  
Vol 78 (1) ◽  
pp. 139-148
Author(s):  
R B Painter
Keyword(s):  
Ionizing Radiation ◽  
Excision Repair ◽  
Double Strand Breaks ◽  
Single Strand ◽  
Premature Aging ◽  
Cross Linking ◽  
Base Damage ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Post Replication Repair

ABSTRACT Damage in DNA after irradiation can be classified into five kinds: base damage, single-strand breaks, double-strand breaks, DNA-DNA cross-linking, and DNA-protein cross-linking. Of these, repair of base damage is the best understood. In eukaryotes, at least three repair systems are known that can deal with base damage: photoreactivation, excision repair, and post-replication repair. Photoreactivation is specific for UV-induced damage and occurs widely throughout the biosphere, although it seems to be absent from placental mammals. Excision repair is present in prokaryotes and in animals but does not seem to be present in plants. Post-replication repair is poorly understood. Recent reports indicate that growing points in mammalian DNA simply skip past UV-induced lesions, leaving gaps in newly made DNA that are subsequently filled in by de novo synthesis. Evidence that this concept is oversimplified or incorrect is presented.—Single-strand breaks are induced by ionizing radiation but most cells can rapidly repair most or all of them, even after supralethal doses. The chemistry of the fragments formed when breaks are induced by ionizing radiation is complex and poorly understood. Therefore, the intermediate steps in the repair of single-strand breaks are unknown. Double-strand breaks and the two kinds of cross-linking have been studied very little and almost nothing is known about their mechanisms for repair.—The role of mammalian DNA repair in mutations is not known. Although there is evidence that defective repair can lead to cancer and/or premature aging in humans, the relationship between the molecular defects and the diseased state remains obscure.

Sulforaphane induces DNA single strand breaks in cultured human cells

2010 ◽  
Vol 689 (1-2) ◽  
pp. 65-73 ◽  
Author(s):  
Piero Sestili ◽  
Marco Paolillo ◽  
Monia Lenzi ◽  
Evelin Colombo ◽  
Luciana Vallorani ◽  
...  
Keyword(s):  
Human Cells ◽  
Single Strand ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Cultured Human Cells

scholarly journals Spatial and Temporal Cellular Responses to Single-Strand Breaks in Human Cells

2003 ◽  
Vol 23 (11) ◽  
pp. 3974-3981 ◽  
Author(s):  
Satoshi Okano ◽  
Li Lan ◽  
Keith W. Caldecott ◽  
Toshio Mori ◽  
Akira Yasui
Keyword(s):  
Cellular Responses ◽  
Dna Lesions ◽  
Human Cells ◽  
Single Strand ◽  
Nuclear Antigen ◽  
Strand Breaks ◽  
Membrane Filters ◽  
Single Strand Breaks ◽  
Assembly Factor ◽  
Proliferating Cell

ABSTRACT DNA single-strand breaks (SSB) are one of the most frequent DNA lesions produced by reactive oxygen species and during DNA metabolism, but the analysis of cellular responses to SSB remains difficult due to the lack of an experimental method to produce SSB alone in cells. By using human cells expressing a foreign UV damage endonuclease (UVDE) and irradiating the cells with UV through tiny pores in membrane filters, we created SSB in restricted areas in the nucleus by the immediate action of UVDE on UV-induced DNA lesions. Cellular responses to the SSB were characterized by using antibodies and fluorescence microscopy. Upon UV irradiation, poly(ADP-ribose) synthesis occurred immediately in the irradiated area. Simultaneously, but dependent on poly(ADP-ribosyl)ation, XRCC1 was translocated from throughout the nucleus, including nucleoli, to the SSB. The BRCT1 domain of XRCC1 protein was indispensable for its poly(ADP-ribose)-dependent recruitment to the SSB. Proliferating cell nuclear antigen and the p150 subunit of chromatin assembly factor 1 also accumulated at the SSB in a detergent-resistant form, which was significantly reduced by inhibition of poly(ADP-ribose) synthesis. Our results show the importance of poly(ADP-ribosyl)ation in sequential cellular responses to SSB.

scholarly journals Manipulating chromosome structure and metaphase status with ultraviolet light and repair synthesis inhibitors

1985 ◽  
Vol 73 (1) ◽  
pp. 159-186
Author(s):  
A.M. Mullinger ◽  
R.T. Johnson
Keyword(s):  
Simian Virus 40 ◽  
Human Cells ◽  
Single Strand ◽  
Dna Breaks ◽  
Intact Cells ◽  
Repair Synthesis ◽  
Single Strand Break ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Chromosome Decondensation

DNA repair occurs in metaphase-arrested cells in response to ultraviolet irradiation. In the presence of the repair synthesis inhibitors hydroxyurea and 1-beta-D-arabinofuranosylcytosine the chromosomes of such cells, as seen in Carnoy-fixed preparations, are decondensed. The extent of decondensation is related to both the u.v. dose and the duration of incubation in the presence of inhibitors. For any particular cell type there is a reasonable correlation between the amount of decondensation and the number of single-strand DNA breaks generated by the repair process under the same inhibitory conditions, though the chromosome changes continue after the number of single-strand breaks has reached a plateau. The dose response of chromosome decondensation varies between different cell types but is in general correlated with differences in levels of single-strand breaks accumulated under comparable inhibitory conditions. Decondensation can be detected after 0.5 Jm-2 in repair-competent human cells. In human cells defective in excision repair there is much less chromosome decondensation in response to the same u.v. dose and time of repair inhibition. However, a simian virus 40-transformed muntjac cell displays pronounced chromosome decondensation but has limited incision ability. Both chromosome decondensation and single-strand break accumulation in the presence of inhibitors are reversed when DNA precursors are provided, but reversal after higher u.v. doses and longer periods of incubation leads to recondensed chromosomes that are fragmented. Elution of the DNA from such cells through polycarbonate filters under non-denaturing conditions reveals that double-strand DNA breaks are generated during the period of incubation with inhibitors. Although the chromosomes of repair-inhibited metaphase cells are decondensed in fixed preparations, their morphology appears normal in intact cells. The cells also retain a capacity to induce prematurely condensed chromosomes (PCC) when fused with interphase cells: compared with control mitotic cells, the speed of induction is sometimes reduced but the final amount of PCC produced is similar.

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