A COMPONENT OF DNA DOUBLE-STRAND BREAK REPAIR IS DEPENDENT ON THE SPATIAL ORIENTATION OF THE LESIONS WITHIN THE HIGHER-ORDER STRUCTURES OF CHROMATIN

被引:43
作者
JOHNSTON, PJ [1 ]
BRYANT, PE [1 ]
机构
[1] UNIV ST ANDREWS, SCH BIOL & MED SCI, ST ANDREWS KY16 9TS, FIFE, SCOTLAND
关键词
D O I
10.1080/09553009414551571
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
By the use of a modified neutral filter elution procedure variations in the repair of DNA dsb have been observed between the ionizing radiation sensitive mutant xrs-5 and the parent cell line CHO-KI. Conventional neutral filter elution requires harsh lysis conditions to remove higher-order chromatin structures which interfere with elution of DNA containing dsb. By lysing cells with non-ionic detergent in the presence of 2mol dm(-3) salt, histone-depleted structures that retain the higher-order nuclear matrix organization, including chromatin loops, can be produced. Elution from these structures will only occur if two or more dsb lie within a single-looped domain delineated by points of attachment to the nuclear matrix. Repair experiments indicate that in CHO cells repair of dsb in loops containing multiple dsb are repaired with slow kinetics whilst dsb occurring in loops containing single dsb are repaired with fast kinetics. Xrs-5 cells are defective in the repair of multiply damaged loops. This work indicates that the spatial orientation of dsb in the higher-order structures of chromatin are a possible factor in the repair of these lesions.
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页码:531 / 536
页数:6
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