Genome-wide hypermutation in a subpopulation of stationary-phase cells underlies recombination-dependent adaptive mutation

被引:229
作者
Torkelson, J [1 ]
Harris, RS [1 ]
Lombardo, MJ [1 ]
Nagendran, J [1 ]
Thulin, C [1 ]
Rosenberg, SM [1 ]
机构
[1] UNIV ALBERTA,DEPT BIOCHEM,EDMONTON,AB T6G 2H7,CANADA
关键词
adaptive mutation; directed mutation; evolution; recombination; stationary phase;
D O I
10.1093/emboj/16.11.3303
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Stationary-phase mutation in microbes can produce selected ('adaptive') mutants preferentially, In one system, this occurs via a distinct, recombination-dependent mechanism, Two points of controversy have surrounded these adaptive reversions of an Escherichia coli lac mutation. First, are the mutations directed preferentially to the selected gene in a Lamarckian manner? Second, is the adaptive mutation mechanism specific to the F plasmid replicon carrying lac? We report that lac adaptive mutations are associated with hypermutation in unselected genes, in all replicons in the cell. The associated mutations have a similar sequence spectrum to the adaptive reversions. Thus, the adaptive mutagenesis mechanism is not directed to the lac genes, in a Lamarckian manner, nor to the F' replicon carrying lac, Hypermutation was not found in non-revertants exposed to selection. Therefore, the genome-wide hypermutation underlying adaptive mutation occurs in a differentiated subpopulation. The existence of mutable subpopulations in non-growing cells is important in bacterial evolution and could be relevant to the somatic mutations that give rise to cancers in multicellular organisms.
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页码:3303 / 3311
页数:9
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