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  • The EMBO Journal (1999) 18, 5714 - 5723
  • doi:10.1093/emboj/18.20.5714

The Saccharomyces cerevisiae MER3 gene, encoding a novel helicase-like protein, is required for crossover control in meiosis

Takuro Nakagawa1,2 and Hideyuki Ogawa1,3

  1. Department of Biology, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
  2. Present address: Ludwig Institute for Cancer Research, University of California San Diego, La Jolla, CA 92093-0660, USA
  3. Present address: Iwate College of Nursing, Ohgama, Takizawa, Iwate 020-0151, Japan

Correspondence to:

Hideyuki Ogawa, E-mail: hogawa@iwate-nurse.ac.jp

Received 4 May 1999; Accepted 27 August 1999; Revised 9 August 1999

The MER3 gene is identified as a novel meiosis-specific gene, whose transcript is spliced in an MRE2/MER1-dependent manner. The predicted Mer3 protein contains the seven motifs characteristic of the DExH-box type of helicases as well as a putative zinc finger. Double strand breaks (DSBs), the initial changes of DNA in meiotic recombination, do not disappear completely and are hyperresected late in mer3 meiosis, indicating that MER3 is required for the transition of DSBs to later intermediates. A mer3 mutation reduces crossover frequencies, and the remaining crossovers show random distribution along a chromosome, resulting in a high incidence of non-disjunction of homologous chromosomes at the first meiotic division. MER3 appears to be very important for both the DSB transition and crossover control.

  • Keywords:

    • crossing over,
    • helicase,
    • interference,
    • meiosis,
    • recombination