title: Genome-wide characterization of fission yeast DNA replication origins.
abstract: Eukaryotic DNA replication is initiated from multiple origins of replication, but little is known about the global regulation of origins throughout the genome or in different types of cell cycles. Here, we identify 401 strong origins and 503 putative weaker origins spaced in total every 14 kb throughout the genome of the fission yeast Schizosaccharomyces pombe. The same origins are used during premeiotic and mitotic S-phases. We found that few origins fire late in mitotic S-phase and that activating the Rad3 dependent S-phase checkpoint by inhibiting DNA replication had little effect on which origins were fired. A genome-wide analysis of eukaryotic origin efficiencies showed that efficiency was variable, with large chromosomal domains enriched for efficient or inefficient origins. Average efficiency is twice as high during mitosis compared with meiosis, which can account for their different S-phase lengths. We conclude that there is a continuum of origin efficiency and that there is differential origin activity in the mitotic and meiotic cell cycles.
authors.affiliation: Laboratory of Yeast Genetics and Cell Biology, The Rockefeller University, New York, NY 10021, USA. christian.heichinger@rockefeller.edu
authors.forename: Christian
authors.initials: C
authors.lastname: Heichinger
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Penkett
authors.forename: Jürg
authors.initials: J
authors.lastname: Bähler
authors.forename: Paul
authors.initials: P
authors.lastname: Nurse
mesh_terms: D015825:Chromosomes, Fungal / Q000235:genetics; D004261:DNA Replication / Q000235:genetics*; D016681:Genome, Fungal; D008540:Meiosis / Q000235:genetics*; D018741:Replication Origin; D016196:S Phase / Q000235:genetics*; D012568:Schizosaccharomyces / Q000235:genetics*