title: ATR/Mec1 prevents lethal meiotic recombination initiation on partially replicated chromosomes in budding yeast.
abstract: During gamete formation, crossover recombination must occur on replicated DNA to ensure proper chromosome segregation in the first meiotic division. We identified a Mec1/ATR- and Dbf4-dependent replication checkpoint in budding yeast that prevents the earliest stage of recombination, the programmed induction of DNA double-strand breaks (DSBs), when pre-meiotic DNA replication was delayed. The checkpoint acts through three complementary mechanisms: inhibition of Mer2 phosphorylation by Dbf4-dependent Cdc7 kinase, preclusion of chromosomal loading of Rec114 and Mre11, and lowered abundance of the Spo11 nuclease. Without this checkpoint, cells formed DSBs on partially replicated chromosomes. Importantly, such DSBs frequently failed to be repaired and impeded further DNA synthesis, leading to a rapid loss in cell viability. We conclude that a checkpoint-dependent constraint of DSB formation to duplicated DNA is critical not only for meiotic chromosome assortment, but also to protect genome integrity during gametogenesis. DOI:http://dx.doi.org/10.7554/eLife.00844.001.
authors.affiliation: Whitehead Institute for Biomedical Research , Cambridge , United States.
authors.forename: Hannah G
authors.initials: HG
authors.lastname: Blitzblau
authors.forename: Andreas
authors.initials: A
authors.lastname: Hochwagen
mesh_terms: D018797:Cell Cycle Proteins / Q000502:physiology; D015825:Chromosomes, Fungal; D004249:DNA Damage; D004261:DNA Replication; D047908:Intracellular Signaling Peptides and Proteins / Q000502:physiology*; D008540:Meiosis / Q000235:genetics*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*
chemical_list: D018797:Cell Cycle Proteins; C088096:Dbf4 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; C088937:MEC1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases
keywords: DDK; DNA replication; S. cerevisiae; checkpoint; double-strand break; gametogenesis; meiosis