Open AccessReplication-dependent early meiotic requirement for Spo11 and Rad50
Author(s) -
Merino St,
Cummings Wj,
Acharya Sn,
Zolan Me
Publication year - 2000
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.190346097
Subject(s) - synapsis , synaptonemal complex , meiosis , biology , dna replication , homologous recombination , genetics , sister chromatids , rad50 , chromosomal crossover , saccharomyces cerevisiae , replication protein a , microbiology and biotechnology , dna , chromosome , dna binding protein , gene , transcription factor
Spo11 and the Rad50-Mre11 complex have been indirectly implicated in processes associated with DNA replication. These proteins also have been shown to have early meiotic roles essential for the formation of a programmed DNA double-strand break known inSaccharomyces cerevisiae to initiate meiotic recombination. In bothS. cerevisiae and the basidiomyceteCoprinus cinereus ,spo11 andrad50 mutants are defective in chromosome synapsis during meiosis. Here we demonstrate that a partial restoration of synapsis occurs inC. cinereus spo11 andrad50 mutants if premeiotic DNA replication is prevented. Double mutants were constructed withspo11–1 orrad50–4 and another mutant,spo22–1 , which does not undergo premeiotic DNA replication. In both cases, we observed an increase in the percentage of nuclei containing synaptonemal complex (SC) structures, with concomitant decreases in the percentage of nuclei containing axial elements (AE) only or no structures. Both types of double mutants demonstrated significant increases in the average numbers of AE and SC, although SC-containing nuclei did not on average contain more AE than did nuclei showing no synapsis. Our results show that Spo11-induced recombination is not absolutely required for synapsis inC. cinereus , and that the early meiotic role of both Spo11 and Rad50 in SC formation partially depends on premeiotic S phase. This dependency likely reflects either a requirement for these proteins imposed by the premeiotic replication process itself or a requirement for these proteins in synapsis when a sister chromatid (the outcome of DNA replication) is present.