REPAIR OF DNA DOUBLE-STRAND BREAKS IN ESCHERICHIA-COLI, WHICH REQUIRES RECA-FUNCTION AND PRESENCE OF A DUPLICATE GENOME
REPAIR OF DNA DOUBLE-STRAND BREAKS IN ESCHERICHIA-COLI, WHICH REQUIRES RECA-FUNCTION AND PRESENCE OF A DUPLICATE GENOME
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DOI：
10.1016/0022-2836(77)90120-6
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发表时间：
1977-01-01
影响因子：
5.6
通讯作者：
HUTCHINSON, F
中科院分区：
文献类型：
--
作者：
KRASIN, F;HUTCHINSON, F
本文报道了从E. coliK 12细胞中，DNA分子在中性蔗糖梯度上沉降，这与游离DNA分子在大小上接近基因组所预期的一样。γ射线照射氧合细胞产生0.20 DNA双链断裂/千拉德每109道尔顿。在照射后培养在K培养基中生长的细胞，4-5个基因组/细胞，显示双链断裂的修复。在天冬氨酸培养基中生长的细胞中没有发现双链断裂的修复，只有1.3个基因组/细胞，尽管DNA单链断裂仍然被有效修复。recA-或recB-的细胞也不能修复双链断裂。DNA双链断裂的修复可以通过涉及具有相同碱基序列的另一个DNA双螺旋的重组事件发生。
A method was devised for extracting, from E. coli K12 cells, DNA molecules which sedimented on neutral sucrose gradients as would be expected for free DNA molecules approaching the genome in size. Gamma ray irradiation of oxygenated cells produced 0.20 DNA double-strand breaks/kilorad per 109 daltons. Incubation after irradiation of cells grown in K medium, with 4-5 genomes/cell, showed repair of the double-strand breaks. No repair of double-strand breaks was found in cells grown in aspartate medium, with only 1.3 genomes/cell, although DNA single-strand breaks were still efficiently repaired. Cells which were recA- or recB- also did not repair double-strand breaks. Repair of DNA double-strand breaks may occur by a recombinational event involving another DNA double helix with the same base sequence.