S. pombe replication protein Cdc18 (Cdc6) interacts with Swi6 (HP1) heterochromatin protein: Region specific effects and replication timing in the centromere |
| |
| Authors: | Pao-Chen Li Louise Chretien Jocelyn C?té Thomas J Kelly Susan L Forsburg |
| |
| Affiliation: | 1.Program in Molecular and Computational Biology; University of Southern California; Los Angeles, CA;2.Memorial Sloan Kettering Cancer Center; New York, NY USA;3.Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease; Faculty of Medicine; University of Ottawa; Ottawa, ON Canada |
| |
| Abstract: | Heterochromatin in S. pombe is associated with gene silencing at telomeres, the mating locus and centromeres. The compact heterochromatin structure raises the question how it unpacks and reforms during DNA replication. We show that the essential DNA replication factor Cdc18 (CDC6) associates with heterochromatin protein 1 (Swi6) in vivo and in vitro. Biochemical mapping and mutational analysis of the association domains show that the N-terminus of Cdc18 interacts with the chromoshadow domain of Swi6. Mutations in Swi6 that disrupt this interaction disrupt silencing and delay replication in the centromere. A mutation cdc18-I43A that reduces Cdc18 association with Swi6 has no silencing defect at the centromere, but changes Swi6 distribution and accelerates the timing of centromere replication. We suggest that fine tuning of Swi6 association at replication origins is important for negative as well as positive control of replication initiation. |
| |
| Keywords: | fission yeast Cdc18 centromere DNA replication Swi6 |
|
