Open AccessA Conditional Lethal Mutant of Escherichia coli K12 Defective in the 5′ → 3′ Exonuclease Associated with DNA Polymerase I
Author(s) -
E. Bruce Konrad,
I. R. Lehman
Publication year - 1974
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.71.5.2048
Subject(s) - dna polymerase , dna polymerase ii , okazaki fragments , dna polymerase i , polymerase , exonuclease , biology , mutant , microbiology and biotechnology , methyl methanesulfonate , dna polymerase mu , dna clamp , escherichia coli , klenow fragment , recbcd , dna replication , dna , polymerase chain reaction , genetics , circular bacterial chromosome , gene , eukaryotic dna replication , reverse transcriptase
A mutant strain ofE. coli , initially identified by an abnormally high frequency of recombination, has been found to be defective in the 5′ → 3′ exonuclease associated with DNA polymerase I, but not in the polymerase activity. This defect is tolerated at 30°, but is lethal at 43°. Like other polymerase I mutants, the strain is unusually sensitive to methyl methanesulfonate and to ultraviolet irradiation; it is also unable to support the growth of phage λ defective in general recombination, and shows a reduced rate of joining of 10S “Okazaki fragments.” These results demonstrate that a functional DNA polymerase I is essential for normal growth and viability inE. coli K12.