Salganik R I, Dianov G L, Medvedev O A
Institute of Cytology and Genetics Siberian Branch of the USSR Academy of Sciences, Novosibirsk.
FEBS Lett. 1990 Feb 12;261(1):28-30. doi: 10.1016/0014-5793(90)80628-v.
Development of a cluster of point mutations due to the correction of an imperfect hairpin in plasmid DNA was investigated. Plasmid pBR322 DNA containing opposite double-strand DNA lesions in the region of a quasipalindrome was constructed. For this aim plasmid DNA was cleaved at the BamHI site, and cytosine residues of the sticky ends were modified by O-methylhydroxylamine. Modified linearized plasmid DNA was ligated and used for transformation of E.coli cells. Tetracycline-sensitive transformants were selected, and the mutants were characterized by restriction and sequencing analysis. One mutant contained a cluster of point mutations. The distribution of mutations was consistent with the cluster having arisen through correction of the imperfect hairpin formed by the quasipalindrome.
研究了由于质粒DNA中不完全发夹结构的校正而导致的一系列点突变的发生情况。构建了在准回文区域含有相对双链DNA损伤的质粒pBR322 DNA。为此，在BamHI位点切割质粒DNA，并用O-甲基羟胺修饰粘性末端的胞嘧啶残基。将修饰后的线性化质粒DNA连接起来，用于转化大肠杆菌细胞。筛选出对四环素敏感的转化体，并通过限制性内切酶分析和测序分析对突变体进行表征。一个突变体含有一系列点突变。突变的分布与通过准回文形成的不完全发夹结构的校正而产生的聚类一致。
