Instability of a plasmid-borne inverted repeat in Saccharomyces cerevisiae.
Inverted repeated DNA sequences are common in both prokaryotes and eukaryotes. We found that a plasmid-borne 94 base-pair inverted repeat (a perfect palindrome of 47 bp) containing a poly GT sequence is unstable in S. cerevisiae, with a minimal deletion frequency of about 10(-4)/mitotic division. Ten independent deletions had identical end points. Sequence analysis indicated that all deletions were the result of a DNA polymerase slippage event (or a recombination event) involving a 5-bp repeat (5' CGACG 3') that flanked the inverted repeat. The deletion rate and the types of deletions were unaffected by the rad52 mutation. Strains with the pms1 mutation had a 10-fold elevated frequency of instability of the inverted repeat. The types of sequence alterations observed in the pms1 background, however, were different than those seen in either the wild-type or rad52 genetic backgrounds.
Henderson
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Department of Biology, University of North Carolina, Chapel Hill 27599-3280.
Petes
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D001483:Base Sequence; D004260:DNA Repair / Q000235:genetics; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012091:Repetitive Sequences, Nucleic Acid; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D017384:Sequence Deletion
D004271:DNA, Fungal