Insights into mutagenesis using Escherichia coli chromosomal lacZ strains that enable detection of a wide spectrum of mutational events.

ABSTRACT: Strand misalignments at DNA repeats during replication are implicated in mutational hotspots. To study these events, we have generated strains carrying mutations in the Escherichia coli chromosomal lacZ gene that revert via deletion of a short duplicated sequence or by template switching within imperfect inverted repeat (quasipalindrome, QP) sequences. Using these strains, we demonstrate that mutation of the distal repeat of a quasipalindrome, with respect to replication fork movement, is about 10-fold higher than the proximal repeat, consistent with more common template switching on the leading strand. The leading strand bias was lost in the absence of exonucleases I and VII, suggesting that it results from more efficient suppression of template switching by 3' exonucleases targeted to th

SUBMITTER: Seier T 

PROVIDER: S-EPMC3122311 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature