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Mutation spectrum of spontaneous frameshift revertants in yeast using double‐strand gap repair
Author(s) -
Plewa Michael J.,
Kalinowski Douglas P.,
Larimer Frank W.
Publication year - 1992
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.2850200203
Subject(s) - frameshift mutation , reversion , genetics , biology , saccharomyces cerevisiae , mutation , shuttle vector , base pair , mutant , position effect , microbiology and biotechnology , yeast , dna , gene , vector (molecular biology) , phenotype , recombinant dna
A mutation spectrum was constructed from a series of randomly isolated spontaneous His + revertants of the frameshift mutant his4–38 in Saccharomyces cerevisiae. For each true revertant, a 438 bp region encompassing his4–38 on chromosome III was recovered into a shuttle vector by double‐strand gap repair. Of the 45 independent His + revertants sequenced, 44 were −1 base deletions and one revertant was a +2 base insertion. The −1 deletions exhibited a bimodal distribution. Of the bases encompassing the his4–38 region from +153–181, 45% were not involved in a reversion event, although a −1 frameshift within this region will result in a viable His + revertant. Approximately 49% of −1 events occurred within runs of 3 repeated bases. At these sites the strand‐slippage model for frameshift mutation is supported. However, the −1 events occurring at sites of 2 repeated bases and the low frequency (2%) of +2 base insertions suggest that the transiently misaligned template model is a significant mechanism in reversion of his4–38. When the distribution of −1 events at repeated bases was discounted, a hotspot involving a ‐T at position +163 was resolved. © 1992 Wiley‐Liss, Inc.