Rfc5, a small subunit of replication factor C complex, couples DNA replication and mitosis in budding yeast

• Published in: Proceedings of the National Academy of Sciences - PNAS 1996-07, Vol.93 (14), p.7048-7052
• Main Authors: Sugimoto, K. (Nagoya University, Nagoya, Japan.), Shimomura, T, Hashimoto, K, Araki, H, Sugino, A, Matsumoto, K
• Format: Article
• Language: English
• Subjects: ADN; Amino Acid Sequence; Cell Cycle; Cell Cycle Proteins; Cell nucleus; Cells; Cellular biology; Checkpoint Kinase 2; Daughter cells; DIVISION CELLULAIRE; DIVISION CELULAR; DNA; DNA Replication; DNA-Binding Proteins - biosynthesis; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - metabolism; Ethyl Methanesulfonate; EXPRESION GENICA; EXPRESSION DES GENES; GENE; GENES; Genes, Fungal; Genetic mutation; Homeodomain Proteins; Humans; Interphase; Kinetics; L cells; Macromolecular Substances; Minor Histocompatibility Antigens; MITOSE; MITOSIS; Molecular Sequence Data; MUTACION INDUCIDA; Mutagenesis; MUTANT; MUTANTES; Mutation; MUTATION PROVOQUEE; Protein Kinases - metabolism; Protein-Serine-Threonine Kinases; PROTEINAS AGLUTINANTES; PROTEINE DE LIAISON; Proteins; Proto-Oncogene Proteins c-bcl-2; REPLICACION; REPLICATION; Replication Protein C; Repressor Proteins; S Phase; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - cytology; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae - physiology; Saccharomyces cerevisiae Proteins; Sequence Homology, Amino Acid
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.93.14.7048

The inhibition of DNA synthesis prevents mitotic entry through the action of the S phase checkpoint. In the yeast Saccharomyces cerevisiae, an essential protein kinase, Spk1/Mec2/Rad53/Sad1, controls the coupling of S phase to mitosis. In an attempt to identify genes that genetically interact with Spk1, we have isolated a temperature-sensitive mutation, rfc5-1, that can be suppressed by overexpression of SPK1. The RFC5 gene encodes a small subunit of replication factor C complex. At the restrictive temperature, rfc5-1 mutant cells entered mitosis with unevenly separated or fragmented chromosomes, resulting in loss of viability. Thus, the rfc5 mutation defective for DNA replication is also impaired in the S phase checkpoint. Overexpression of POL30, which encodes the proliferating cell nuclear antigen, suppressed the replication defect of the rfc5 mutant but not its checkpoint defect. Taken together, these results suggested that replication factor C has a direct role in sensing the state of DNA replication and transmitting the signal to the checkpoint machinery.