REPAIR OF MMS-INDUCED DNA DOUBLE-STRAND BREAKS IN HAPLOID CELLS OF SACCHAROMYCES-CEREVISIAE, WHICH REQUIRES THE PRESENCE OF A DUPLICATE GENOME
REPAIR OF MMS-INDUCED DNA DOUBLE-STRAND BREAKS IN HAPLOID CELLS OF SACCHAROMYCES-CEREVISIAE, WHICH REQUIRES THE PRESENCE OF A DUPLICATE GENOME
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DOI：
10.1007/bf00267420
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发表时间：
1979-01-01
期刊：
影响因子：
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通讯作者：
JACHYMCZYK, WJ
中科院分区：
文献类型：
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作者：
CHLEBOWICZ, E;JACHYMCZYK, WJ
采用中性和碱性蔗糖沉降技术，研究了MMS（甲磺酸甲酯）对酿酒酵母单倍体野生型和MMS敏感的rad6突变株DNA双链断裂的形成和修复。双链DNA的平均分子量也有类似的下降，从5-6倍。108到1-0.7倍。0.5% MMS处理后，野生型和突变株的道尔顿数为108。MMS处理后的细胞在新鲜的无药物生长培养基中孵育导致野生型菌株双链断裂的修复，但仅在生长的指数阶段。在G-1期对野生型菌株进行细胞同步处理时，未发现双链断裂的修复。尽管DNA单链断裂仍能有效修复。突变体rad6修复mms诱导的单链断裂的能力非常低，无论生长阶段如何，都不能修复双链断裂。双链断裂的修复可能需要单链断裂的修复能力，而双链断裂的重新连接显然需要2个同源DNA分子的可用性，这有力地支持了DNA修复的重组模型。
The formation and repair of double-strand breaks induced in DNA by MMS [methyl methanesulfonate] was studied in haploid wild type and MMS-sensitive rad6 mutant strains of S. cerevisiae with the use of the neutral and alkaline sucrose sedimentation technique. A similar decrease in average MW of double-stranded DNA from 5-6 .times. 108 to 1-0.7 .times. 108 daltons was observed following treatment with 0.5% MMS in wild type and mutant strains. Incubation of cells after MMS treatment in a fresh drug-free growing medium resulted in repair of double-strand breaks in the wild type strain, but only in the exponential phase of growth. No repair of double-strand breaks was found when cells of the wild type strain were synchronized in G-1 phase by treatment with .alpha. factor, although DNA single-strand breaks were still efficiently repaired. Mutant rad6 which has a very low ability to repair MMS-induced single-strand breaks, did not repair double-strand breaks regardless of the phase of growth. Repair of double-strand breaks probably requires the ability for single-strand breaks repair, and rejoining of double-strand breaks apparently requires the availability of 2 homologous DNA molecules, strongly supporting the recombinational model of DNA repair.