Both a Unique Motif at the C Terminus and an N-Terminal HEAT Repeat Contribute to G-Quadruplex Binding and Origin Regulation by the Rif1 Protein
| Autor: | Naoko Kakusho, Seiji Matsumoto, Rino Fukatsu, Yutaka Kanoh, Shigeru Chaen, Hisao Masai, Shunsuke Kobayashi |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
DNA Replication
Telomere-Binding Proteins Phosphatase HEAT repeat Cell Cycle Proteins Replication Origin Protein Serine-Threonine Kinases Biology G-quadruplex 03 medical and health sciences 0302 clinical medicine Protein Domains Schizosaccharomyces Amino Acid Sequence Molecular Biology 030304 developmental biology chemistry.chemical_classification 0303 health sciences Point mutation C-terminus Terminal Repeat Sequences DNA replication Cell Biology Cdc7/Hsk1 Yeast Chromatin Cell biology Amino acid DNA-Binding Proteins G-Quadruplexes Repressor Proteins chemistry Schizosaccharomyces pombe Proteins 030217 neurology & neurosurgery Protein Binding Research Article |
| Zdroj: | Molecular and Cellular Biology |
| ISSN: | 1098-5549 |
| DOI: | 10.1128/mcb.00364-18 |
| Popis: | Rif1 is a key factor for spatiotemporal regulation of DNA replication. Rif1 suppresses origin firing in the mid-late replication domains by generating replication-suppressive chromatin architecture and by recruiting a protein phosphatase. Rif1 is a key factor for spatiotemporal regulation of DNA replication. Rif1 suppresses origin firing in the mid-late replication domains by generating replication-suppressive chromatin architecture and by recruiting a protein phosphatase. In fission yeast, the function of Hsk1, a kinase important for origin firing, can be bypassed by rif1Δ due to the loss of origin suppression. Rif1 specifically binds to G-quadruplex (G4) in vitro. Here, we show both conserved N-terminal HEAT repeats and C-terminal nonconserved segments are required for origin suppression. The N-terminal 444 amino acids and the C-terminal 229 amino acids can each mediate specific G4 binding, although high-affinity G4 binding requires the presence of both N- and C-terminal segments. The C-terminal 91 amino acids, although not able to bind to G4, can form a multimer. Furthermore, genetic screening led to identification of two classes of rif1 point mutations that can bypass Hsk1, one that fails to bind to chromatin and one that binds to chromatin. These results illustrate functional domains of Rif1 and indicate importance of both the N-terminal HEAT repeat segment and C-terminal G4 binding/oligomerization domain as well as other functionally unassigned segments of Rif1 in regulation of origin firing. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|