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A site‐ and strand‐specific DNA break confers asymmetric switching potential in fission yeast
Author(s) -
Arcangioli Benoit
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.15.4503
Subject(s) - biology , yeast , fission , dna , schizosaccharomyces , genetics , saccharomyces cerevisiae , microbiology and biotechnology , schizosaccharomyces pombe , physics , neutron , quantum mechanics
Mating‐type switching in the fission yeast Schizosaccharomyces pombe results in the transfer of genetic information from one of the two silent cassettes ( mat2 P or mat3 M) to the transcriptionally active locus ( mat1 ). The switching pattern is programmed by an imprinting event which restricts mat1 gene conversion to only one of the two sister cells, leading to asymmetric cell division. Biochemical analysis indicated that the mat1 locus contains a fragile chromosomal site. Southern hybridization and primer extension experiments showed that the fragility consists of a single‐strand break (SSB). The nicked DNA is stable throughout the cell cycle. The features of the nick fulfil all the requirements for the ‘epigenetic’, site and strand‐specific chromosome modification at the mat1 locus, providing strong evidence that an SSB can initiate mitotic and meiotic gene conversion during replication.