Bachl J, Dessing M, Olsson C, von Borstel R C, Steinberg C
Basel Institute for Immunology, Postfach, CH-4005 Basel, Switzerland.
Proc Natl Acad Sci U S A. 1999 Jun 8;96(12):6847-9. doi: 10.1073/pnas.96.12.6847.
A cell line harboring all trans-acting elements necessary for hypermutation was transfected with a plasmid harboring the major cis-acting elements plus a green fluorescent protein gene containing a premature chain-termination codon. Transfected cells do not fluoresce unless the stop codon reverts. When a sizable cell population is purged of revertants by sorting, the frequency of mutants increases linearly with time, and there is no Luria-Delbrück fluctuation effect. Moreover, as mutant frequencies seemed to vary less than cell numbers in replicate cultures, it is suggested that hypermutation might not be coupled closely to cell division.
将携带高突变所需所有反式作用元件的细胞系用携带主要顺式作用元件的质粒以及含有提前链终止密码子的绿色荧光蛋白基因进行转染。除非终止密码子回复突变,否则转染的细胞不会发出荧光。当通过分选清除相当数量的回复突变体后,突变体的频率随时间呈线性增加,并且不存在卢里亚-德尔布吕克波动效应。此外,由于在重复培养中突变频率的变化似乎小于细胞数量的变化,因此有人提出高突变可能与细胞分裂没有紧密联系。