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Cluster of point mutations predetermined by a quasipalindromic nucleotide sequence in plasmid pBR322 DNA
Author(s) -
Salganik R.I.,
Dianov G.L.,
Medvedev O.A.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80628-v
Subject(s) - plasmid , point mutation , pbr322 , dna , bamhi , microbiology and biotechnology , genetics , transformation (genetics) , restriction site , biology , cytosine , restriction map , base pair , mutation , mutant , dna sequencing , restriction enzyme , gene
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 Bam HI 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.