PREFERENTIAL UNEQUAL RECOMBINATION IN THE GLYS REGION OF THE ESCHERICHIA-COLI CHROMOSOME
PREFERENTIAL UNEQUAL RECOMBINATION IN THE GLYS REGION OF THE ESCHERICHIA-COLI CHROMOSOME
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DOI：
10.1016/0022-2836(79)90460-1
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发表时间：
1979-01-01
影响因子：
5.6
通讯作者：
HILL, CW
中科院分区：
文献类型：
--
作者：
CAPAGE, M;HILL, CW
E.携带glyS和xyl基因座的大肠杆菌染色体区域可以通过对trpA 36 glySL glyTsuAGA（或glycoprotein AGA）培养物进行脱氧腺苷处理来选择。脱氧腺苷降低了这些错义抑制因子的抑制效率;生长受到由此产生的色氨酸饥饿的严重限制。用250 μ g脱氧腺苷/ml延长生长导致具有2个（或更多个）甘氨酰转移RNA合成酶glySL的等位基因拷贝的突变体的积累。每次施加选择性压力时都获得相同的复制。这通过以环状DNA的形式物理分离复制区域来显示，所述环状DNA通过重组从复制中切除。在重复的实验中，分离出一个大小为140，000个碱基对的圆形物种。有2个基因座，glyS基因座的每一侧各1个，间隔140，000个碱基对，它们倾向于以导致遗传复制的方式彼此重组。
Duplications of the E. coli chromosomal region carrying the glyS and xyl loci can be selected by deoxyadenosine treatment of trpA36 glySL glyTsuAGA (or glyUsuAGA) cultures. The deoxyadenosine lowers the suppression efficiency of these missense suppressors; growth is severely limited by the resulting tryptophan starvation. Prolonged growth with 250 .mu.g deoxyadenosine/ml leads to the accumulation of mutants with 2 (or more) copies of the allele for glycyl-transfer RNA synthetase, glySL. The same duplication is obtained each time the selective pressure is applied. This was shown by physically isolating the duplicated region in the form of circular DNA excised from the duplication by recombination. In repeated experiments, a circular species 140,000 base-pairs in size was isolated. There are 2 loci, 1 on each side of the glyS locus, spaced 140,000 base-pairs apart, which are prone to recombining with each other in a manner leading to a genetic duplication.