Factors that affect the location and frequency of meiosis-induced double-strand breaks in Saccharomyces cerevisiae.
Double-strand DNA breaks (DSBs) initiate meiotic recombination in Saccharomyces cerevisiae. DSBs occur at sites that are hypersensitive in nuclease digests of chromatin, suggesting a role for chromatin structure in determining DSB location. We show here that the frequency of DSBs at a site is not determined simply by DNA sequence or by features of chromatin structure. An arg4-containing plasmid was inserted at several different locations in the yeast genome. Meiosis-induced DSBs occurred at similar sites in pBR322-derived portions of the construct at all insert loci, and the frequency of these breaks varied in a manner that mirrored the frequency of meiotic recombination in the arg4 portion of the insert. However, DSBs did not occur in the insert-borne arg4 gene at a site that is frequently broken at the normal ARG4 locus, even though the insert-borne arg4 gene and the normal ARG4 locus displayed similar DNase I hypersensitivity patterns. Deletions that removed active DSB sites from an insert at HIS4 restored breaks to the insert-borne arg4 gene and to a DSB site in flanking chromosomal sequences. We conclude that the frequency of DSB at a site can be affected by sequences several thousand nucleotides away and suggest that this is because of competition between DSB sites for locally limited factors.
Wu
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Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892, USA.
Lichten
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D001123:Argininosuccinate Lyase; D002843:Chromatin / Q000378:metabolism / Q000648:ultrastructure; D003434:Crossing Over, Genetic; D004247:DNA / Q000235:genetics*; D004249:DNA Damage; D004271:DNA, Fungal / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics; D008540:Meiosis; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion
D002843:Chromatin; D004271:DNA, Fungal; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA; C087900:Arg4 protein, S cerevisiae; D001123:Argininosuccinate Lyase