Rfc4 interacts with Rpa1 and is required for both DNA replication and DNA damage checkpoints in Saccharomyces cerevisiae.

The large subunit of replication protein A (Rpa1) consists of three single-stranded DNA binding domains and an N-terminal domain (Rpa1N) of unknown function. To determine the essential role of this domain we searched for mutations that require wild-type Rpa1N for viability in yeast. A mutation in RFC4, encoding a small ...
subunit of replication factor C (RFC), was found to display allele-specific interactions with mutations in the gene encoding Rpa1 (RFA1). Mutations that map to Rpa1N and confer sensitivity to the DNA synthesis inhibitor hydroxyurea, such as rfa1-t11, are lethal in combination with rfc4-2. The rfc4-2 mutant itself is sensitive to hydroxyurea, and like rfc2 and rfc5 strains, it exhibits defects in the DNA replication block and intra-S checkpoints. RFC4 and the DNA damage checkpoint gene RAD24 were found to be epistatic with respect to DNA damage sensitivity. We show that the rfc4-2 mutant is defective in the G(1)/S DNA damage checkpoint response and that both the rfc4-2 and rfa1-t11 strains are defective in the G(2)/M DNA damage checkpoint. Thus, in addition to its essential role as part of the clamp loader in DNA replication, Rfc4 plays a role as a sensor in multiple DNA checkpoint pathways. Our results suggest that a physical interaction between Rfc4 and Rpa1N is required for both roles.
Mesh Terms:
Cell Cycle Proteins, DNA Damage, DNA Replication, DNA, Fungal, DNA-Binding Proteins, Homeodomain Proteins, Intracellular Signaling Peptides and Proteins, Mutagenesis, Proto-Oncogene Proteins c-bcl-2, Replication Protein A, Replication Protein C, Repressor Proteins, S Phase, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Signal Transduction
Mol. Cell. Biol.
Date: Jun. 01, 2001
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