Riedinger K L, Hanford M G, Farber R A
Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill 27599-7525, USA.
Environ Mol Mutagen. 1996;28(3):276-83. doi: 10.1002/(SICI)1098-2280(1996)28:3<276::AID-EM12>3.0.CO;2-C.
A cultured mouse cell line with an integrated copy of a plasmid that contains a short dinucleotide repeat sequence (microsatellite) has been used to determine the frequencies and types of mutation induced by two frameshift mutagens. The presence of the microsatellite, which consists of 17 repeats of a poly(dC-dA).poly(dT-dG) sequence, disrupts the reading frame of a gene coding for neomycin resistance. Revertants were selected in G418, and mutations were analyzed by PCR. ICR-170 was found to increase the reversion frequency by ten- to 15-fold at its LD50, although most of the frameshifts that it induced were single-base insertions outside the microsatellite sequence. NA-AAF brought about a more modest increase in mutation frequency, but nearly all of the revertants in the NA-AAF-treated cultures had insertions or deletions of multiples of two base pairs within the DNA segment that included the microsatellite. This system can be modified to include different short tandem repeat sequences as targets for testing of compounds that are suspected of having frameshift-inducing activities.
一种具有整合质粒拷贝的培养小鼠细胞系被用于确定两种移码诱变剂诱导的突变频率和类型，该质粒含有短二核苷酸重复序列（微卫星）。微卫星由17个聚（dC-dA）.聚（dT-dG）序列重复组成，它破坏了编码新霉素抗性的基因的阅读框。在G418中筛选回复突变体，并通过PCR分析突变。发现ICR-170在其半数致死剂量时使回复频率提高了10到15倍，尽管它诱导的大多数移码是微卫星序列外的单碱基插入。NA-AAF使突变频率有更适度的增加，但在经NA-AAF处理的培养物中，几乎所有回复突变体在包含微卫星的DNA片段内都有两个碱基对倍数的插入或缺失。该系统可以进行修改，以纳入不同的短串联重复序列作为测试疑似具有移码诱导活性化合物的靶点。
