Michael Lichten

Publications (55) View all

• Article: Differential timing and control of noncrossover and crossover recombination during meiosis.

  T Allers, M Lichten
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  ABSTRACT: Unitary models of meiotic recombination postulate that a central intermediate containing Holliday junctions is resolved to generate either noncrossover or crossover recombinants, both of which contain heteroduplex DNA. Contrary to this expectation, we find that during meiosis in Saccharomyces cerevisiae, noncrossover heteroduplex products are formed at the same time as Holliday junction intermediates. Crossovers appear later, when these intermediates are resolved. Furthermore, noncrossover and crossover recombination are regulated differently. ndt80 mutants arrest in meiosis with unresolved Holliday junction intermediates and very few crossovers, while noncrossover heteroduplex products are formed at normal levels and with normal timing. These results suggest that crossovers are formed by resolution of Holliday junction intermediates, while most noncrossover recombinants arise by a different, earlier pathway.
  Cell 08/2001; 106(1):47-57. · 32.40 Impact Factor
• Article: Intermediates of yeast meiotic recombination contain heteroduplex DNA.

  T Allers, M Lichten
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  ABSTRACT: The formation of heteroduplex DNA features prominently in all models for homologous recombination. A central intermediate in the current double-strand break repair model contains two Holliday junctions flanking a region of heteroduplex DNA. Studies of yeast meiosis have identified such intermediates but failed to detect associated heteroduplex DNA. We show here that these intermediates contain heteroduplex DNA, providing an important validation of the double-strand break repair model. However, we also detect intermediates where both Holliday junctions are to one side of the initiating DSB site, while the intervening region shows no evidence of heteroduplex DNA. Such structures are not easily accommodated by the canonical version of the double-strand break repair model.
  Molecular Cell 08/2001; 8(1):225-31. · 14.18 Impact Factor
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  Article: Meiotic recombination: breaking the genome to save it.

  M Lichten
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  ABSTRACT: Recombination ensures the correct segregation of chromosomes to gametes during meiosis. Recent studies point to a universal mechanism for initiating meiotic recombination: the formation of double-strand DNA breaks by Spo11p.
  Current Biology 05/2001; 11(7):R253-6. · 9.65 Impact Factor
• Article: Gamma-H2AX illuminates meiosis.

  N Hunter, G V Börner, M Lichten, N Kleckner
  Nature Genetics 04/2001; 27(3):236-8. · 35.53 Impact Factor
• Article: Direct coupling between meiotic DNA replication and recombination initiation.

  V Borde, A S Goldman, M Lichten
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  ABSTRACT: During meiosis in Saccharomyces cerevisiae, DNA replication occurs 1. 5 to 2 hours before recombination initiates by DNA double-strand break formation. We show that replication and recombination initiation are directly linked. Blocking meiotic replication prevented double-strand break formation in a replication-checkpoint-independent manner, and delaying replication of a chromosome segment specifically delayed break formation in that segment. Consequently, the time between replication and break formation was held constant in all regions. We suggest that double-strand break formation occurs as part of a process initiated by DNA replication, which thus determines when meiotic recombination initiates on a regional rather than a cell-wide basis.
  Science 11/2000; 290(5492):806-9. · 31.20 Impact Factor