Publications [#228479] of Steven B. Haase

Papers Published

1. Kiely, J; Haase, SB; Russell, P; Leatherwood, J, Functions of fission yeast orp2 in DNA replication and checkpoint control., Genetics, vol. 154 no. 2 (February, 2000), pp. 599-607, ISSN 0016-6731 [doi]
   (last updated on 2026/01/16)

   Abstract:
   orp2 is an essential gene of the fission yeast Schizosaccharomyces pombe with 22% identity to budding yeast ORC2. We isolated temperature-sensitive alleles of orp2 using a novel plasmid shuffle based on selection against thymidine kinase. Cells bearing the temperature-sensitive allele orp2-2 fail to complete DNA replication at a restrictive temperature and undergo cell cycle arrest. Cell cycle arrest depends on the checkpoint genes rad1 and rad3. Even when checkpoint functions are wild type, the orp2-2 mutation causes high rates of chromosome and plasmid loss. These phenotypes support the idea that Orp2 is a replication initiation factor. Selective spore germination allowed analysis of orp2 deletion mutants. These experiments showed that in the absence of orp2 function, cells proceed into mitosis despite a lack of DNA replication. This suggests either that the Orp2 protein is a part of the checkpoint machinery or more likely that DNA replication initiation is required to induce the replication checkpoint signal.