Abstract
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.
Original language | English (US) |
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Pages (from-to) | 84-88 |
Number of pages | 5 |
Journal | Environmental and Molecular Mutagenesis |
Volume | 20 |
Issue number | 2 |
DOIs | |
State | Published - 1992 |
Keywords
- HIS4, Saccharomyces cerevisiae
- strand slippage
- transient misalignment
ASJC Scopus subject areas
- Epidemiology
- Genetics(clinical)
- Health, Toxicology and Mutagenesis