Identification of two telomere-proximal fission yeast DNA replication origins constrained by nearby cis-acting sequences to replicate in late S phase [v1; ref status: indexed, http://f1000r.es/SuWYQb]

• Main Authors: Amna Chaudari, Joel A Huberman
• Format: Article
• Language: English
• Published: F1000 Research Ltd 2012-12-01
• Series: F1000Research
• Subjects: Cell Growth & Division; Microbial Growth & Development; Nuclear Structure & Function
• Online Access: http://f1000research.com/articles/1-58/v1

Telomeres of the fission yeast, Schizosaccharomyces pombe, are known to replicate in late S phase, but the reasons for this late replication are not fully understood. We have identified two closely-spaced DNA replication origins, 5.5 to 8 kb upstream from the telomere itself. These are the most telomere-proximal of all the replication origins in the fission yeast genome. When located by themselves in circular plasmids, these origins fired in early S phase, but if flanking sequences closer to the telomere were included in the circular plasmid, then replication was restrained to late S phase – except in cells lacking the replication-checkpoint kinase, Cds1. We conclude that checkpoint-dependent late replication of telomere-associated sequences is dependent on nearby cis-acting sequences, not on proximity to the physical end of a linear chromosome.