Loss of Cell Cycle Checkpoint Control in Drosophila Rfc4 Mutants

ABSTRACT Two alleles of the Drosophila melanogaster Rfc4(DmRfc4) gene, which encodes subunit 4 of the replication factor C (RFC) complex, cause striking defects in mitotic chromosome cohesion and condensation. These mutations produce larval phenotypes consistent with a role in DNA replication but also result in mitotic chromosomal defects appearing either as premature chromosome condensation-like or precocious sister chromatid separation figures. Though the DmRFC4 protein localizes to all replicating nuclei, it is dispersed from chromatin in mitosis. Thus the mitotic defects appear not to be the result of a direct role for RFC4 in chromosome structure. We also show that the mitotic defects in these twoDmRfc4 alleles are the result of aberrant checkpoint control in response to DNA replication inhibition or damage to chromosomes. Not all surveillance function is compromised in these mutants, as the kinetochore attachment checkpoint is operative. Intriguingly, metaphase delay is frequently observed with the more severe of the two alleles, indicating that subsequent chromosome segregation may be inhibited. This is the first demonstration that subunit 4 of RFC functions in checkpoint control in any organism, and our findings additionally emphasize the conserved nature of RFC's involvement in checkpoint control in multicellular eukaryotes.

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Extragenic suppressors of Schizosaccharomyces pombe rad9 mutations uncouple radioresistance and hydroxyurea sensitivity from cell cycle checkpoint control.

Genetics ◽

10.1093/genetics/141.1.107 ◽

1995 ◽

Vol 141 (1) ◽

pp. 107-117

Author(s):

H B Lieberman

Keyword(s):

Dna Replication ◽

Ionizing Radiation ◽

Schizosaccharomyces Pombe ◽

Uv Light ◽

Acquired Resistance ◽

Cell Cycle Checkpoint ◽

Moderate Increase ◽

Checkpoint Control ◽

Cycle Checkpoint ◽

Derivatives Of

Abstract Schizosaccharomyces pombe cells that contain a mutation within rad9 are sensitive to ionizing radiation, UV light and hydroxyurea, relative to wild-type strains. In addition, the mutants are moderately hypomutable by UV and unable to delay initiation of mitosis after treatment with radiation or hydroxyurea. Three radioresistant derivatives of rad9::ura4 cells were isolated, and each contained a single unique extragenic suppressor responsible for the acquired resistance. The suppressor loci also conferred radioresistance upon cells containing rad9-192, which differs from rad9+ by a single base pair change. The suppressors additionally enhanced the radioresistance of cells containing rad3-136, a mutation that leads to phenotypes similar to those mediated by rad9::ura4. None of the derivatives of rad9::ura4 cells recovered the ability to delay cycling in G2 after exposure to ionizing radiation or UV light. All three suppressor derivatives, relative to the parental rad9::ura4 strain, also exhibited a moderate increase in resistance to the DNA replication inhibitor hydroxyurea without gaining the ability to stop progression into mitosis despite the inhibition of DNA synthesis. Results are discussed in terms of models to explain the putative role of rad9 and the suppressor genes in promoting radioresistance and mediating checkpoint controls responsive to DNA damage or incomplete DNA replication.

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A coordinated interplay: Proteins with multiple functions in DNA replication, DNA repair, cell cycle/ checkpoint control, and transcription

Progress in Nucleic Acid Research and Molecular Biology ◽

10.1016/s0079-6603(00)65007-9 ◽

2000 ◽

pp. 261-298 ◽

Cited By ~ 26

Author(s):

Manuel Stucki ◽

Igor Stagljar ◽

Zophonias O. Jonsson ◽

Ulrich Hübscher

Keyword(s):

Cell Cycle ◽

Dna Repair ◽

Dna Replication ◽

Cell Cycle Checkpoint ◽

Checkpoint Control ◽

Multiple Functions ◽

Cycle Checkpoint

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Attenuation of G 2 -Phase Cell Cycle Checkpoint Control Is Associated with Increased Frequencies of Unrejoined Chromosome Breaks in Human Tumor Cells

Radiation Research ◽

10.2307/3579585 ◽

1996 ◽

Vol 146 (2) ◽

pp. 139 ◽

Cited By ~ 7

Author(s):

Jeffrey L. Schwartz ◽

Janet Cowan ◽

David J. Grdina ◽

Ralph R. Weichselbaum

Keyword(s):

Cell Cycle ◽

Tumor Cells ◽

Human Tumor ◽

Cell Cycle Checkpoint ◽

Phase Cell ◽

Checkpoint Control ◽

Human Tumor Cells ◽

Chromosome Breaks ◽

Cycle Checkpoint

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The Large Subunit of Replication Factor C (Rfclp/Cdc44p) Is Required for DNA Replication and DNA Repair in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/142.1.65 ◽

1996 ◽

Vol 142 (1) ◽

pp. 65-78 ◽

Cited By ~ 7

Author(s):

Michael A McAlear ◽

K Michelle Tuffo ◽

Connie Holm

Keyword(s):

Saccharomyces Cerevisiae ◽

Dna Repair ◽

Dna Replication ◽

Uv Radiation ◽

Large Subunit ◽

Restrictive Temperature ◽

Replication Factor C ◽

Replication Factor ◽

Factor C

We used genetic and biochemical techniques to characterize the phenotypes associated with mutations affecting the large subunit of replication factor C (Cdc44p or Rfc1p) in Saccharomyces cerevisiae. We demonstrate that Cdc44p is required for both DNA replication and DNA repair in vivo. Cold-sensitive cdc44 mutants experience a delay in traversing S phase at the restrictive temperature following alpha factor arrest; although mutant cells eventually accumulate with a G2/M DNA content, they undergo a cell cycle arrest and initiate neither mitosis nor a new round of DNA synthesis. cdc44 mutants also exhibit an elevated level of spontaneous mutation, and they are sensitive both to the DNA damaging agent methylmethane sulfonate and to exposure to UV radiation. After exposure to UV radiation, cdc44 mutants at the restrictive temperature contain higher levels of single-stranded DNA breaks than do wild-type cells. This observation is consistent with the hypothesis that Cdc44p is involved in repairing gaps in the DNA after the excision of damaged bases. Thus, Cdc44p plays an important role in both DNA replication and DNA repair in vivo.

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Determination of the Genotype of a Panel of Human Tumor Cell Lines for the Human Homologues of Yeast Cell Cycle Checkpoint Control Genes: Identification of Cell Lines Carrying Homoallelic Missense Base Substitutions

Somatic Cell and Molecular Genetics ◽

10.1023/b:scam.0000007139.83021.fc ◽

1999 ◽

Vol 25 (1) ◽

pp. 41-48 ◽

Cited By ~ 6

Author(s):

Yosuke Ejima ◽

Lichun Yang

Keyword(s):

Cell Cycle ◽

Cell Lines ◽

Human Tumor ◽

Cell Cycle Checkpoint ◽

Tumor Cell Lines ◽

Checkpoint Control ◽

Human Tumor Cell ◽

Human Tumor Cell Lines ◽

Cycle Checkpoint

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Identification of replication factor C from Saccharomyces cerevisiae: a component of the leading-strand DNA replication complex

Molecular and Cellular Biology ◽

10.1128/mcb.12.1.155-163.1992 ◽

1992 ◽

Vol 12 (1) ◽

pp. 155-163 ◽

Cited By ~ 1

Author(s):

K Fien ◽

B Stillman

Keyword(s):

Saccharomyces Cerevisiae ◽

Dna Replication ◽

Dna Polymerase ◽

Replication Factor C ◽

Dna Polymerase Delta ◽

Replication Complex ◽

Leading Strand ◽

Factor C ◽

Sv40 Dna

A number of proteins have been isolated from human cells on the basis of their ability to support DNA replication in vitro of the simian virus 40 (SV40) origin of DNA replication. One such protein, replication factor C (RFC), functions with the proliferating cell nuclear antigen (PCNA), replication protein A (RPA), and DNA polymerase delta to synthesize the leading strand at a replication fork. To determine whether these proteins perform similar roles during replication of DNA from origins in cellular chromosomes, we have begun to characterize functionally homologous proteins from the yeast Saccharomyces cerevisiae. RFC from S. cerevisiae was purified by its ability to stimulate yeast DNA polymerase delta on a primed single-stranded DNA template in the presence of yeast PCNA and RPA. Like its human-cell counterpart, RFC from S. cerevisiae (scRFC) has an associated DNA-activated ATPase activity as well as a primer-template, structure-specific DNA binding activity. By analogy with the phage T4 and SV40 DNA replication in vitro systems, the yeast RFC, PCNA, RPA, and DNA polymerase delta activities function together as a leading-strand DNA replication complex. Now that RFC from S. cerevisiae has been purified, all seven cellular factors previously shown to be required for SV40 DNA replication in vitro have been identified in S. cerevisiae.

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DNA damage checkpoint kinases in cancer

Expert Reviews in Molecular Medicine ◽

10.1017/erm.2020.3 ◽

2020 ◽

Vol 22 ◽

Cited By ~ 7

Author(s):

Hannah L. Smith ◽

Harriet Southgate ◽

Deborah A. Tweddle ◽

Nicola J. Curtin

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Environmental Dna ◽

Cell Cycle Checkpoint ◽

Checkpoint Control ◽

Integrated Network ◽

Checkpoint Kinases ◽

G1 Checkpoint ◽

Cycle Checkpoint ◽

High Level

Abstract DNA damage response (DDR) pathway prevents high level endogenous and environmental DNA damage being replicated and passed on to the next generation of cells via an orchestrated and integrated network of cell cycle checkpoint signalling and DNA repair pathways. Depending on the type of damage, and where in the cell cycle it occurs different pathways are involved, with the ATM-CHK2-p53 pathway controlling the G1 checkpoint or ATR-CHK1-Wee1 pathway controlling the S and G2/M checkpoints. Loss of G1 checkpoint control is common in cancer through TP53, ATM mutations, Rb loss or cyclin E overexpression, providing a stronger rationale for targeting the S/G2 checkpoints. This review will focus on the ATM-CHK2-p53-p21 pathway and the ATR-CHK1-WEE1 pathway and ongoing efforts to target these pathways for patient benefit.

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