Glazunov A V, Glazer V M, Perera D R, Boreĭko A V
Mol Gen Mikrobiol Virusol. 1987 Aug(8):19-25.
The efficiency of "LiCl transformation" in Saccharomyces cerevisiae haploid cells by an autonomously replicating pLL12 plasmid carrying yeast LEU2 and LYS2 genes is increased (by an order or more) when the plasmid is linearized by the restriction endonuclease XhoI cleavage of a unique site in LYS2 gene. Transformants were selected on the medium lacking leucine. This phenomenon has been shown to be a result of recombinational repair of double-strand breaks (DSB) of plasmid DNA stimulated by a restriction endonuclease. The kinetic data have shown the process of plasmid DNA DSB repair to consist of two phases. The completion of the first phase occurs during an hour and the second phase occurs in 14-18 hours. DNA double-strand gaps (the deleted sequences of plasmid LYS2 gene in DSB region) with maximal length of 2-2.5 kb are repaired with the same efficiency as DSB. The genetic control of the recombinational repair of plasmid DNA DSB has been studied.
当携带酵母LEU2和LYS2基因的自主复制型pLL12质粒通过限制性内切核酸酶XhoI切割LYS2基因中的一个特定位点而线性化时，酿酒酵母单倍体细胞中“LiCl转化”的效率会提高（提高一个数量级或更多）。在缺乏亮氨酸的培养基上选择转化子。已证明这种现象是由限制性内切核酸酶刺激的质粒DNA双链断裂（DSB）的重组修复导致的。动力学数据表明，质粒DNA DSB修复过程由两个阶段组成。第一阶段在一小时内完成，第二阶段在14 - 18小时内发生。最大长度为2 - 2.5 kb的DNA双链缺口（DSB区域中质粒LYS2基因的缺失序列）与DSB以相同效率修复。已研究了质粒DNA DSB重组修复的遗传控制。
