Mutant alleles of Schizosaccharomyces pombe rad9+ alter hydroxyurea resistance, radioresistance and checkpoint control

Hang, Haiying; Rauth, Sarah J.; Hopkins, Kevin M.; Lieberman, Howard B.

doi:10.1093/nar/28.21.4340

Cited by 9 publications

(5 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This method of synchronization has been widely and successfully used to assess the functionality of the G 2 DNA damage checkpoint in wild-type and checkpoint mutants upon ionizing radiation, UVC light and treatment with drugs that produce covalent interstrand cross-links. 39,[41][42][43][44] Cells synchronized in G 2 phase contain 1 single nucleus with 2C DNA content. After exposure to different UVA doses, synchronized cells were released into cell cycle (time 0) whose progression was figure 3A, the appearance of cells with 2 nuclei was delayed by UVA in all tested strains.…”

Section: Resultsmentioning

confidence: 99%

Unconventional effects of UVA radiation on cell cycle progression inS. pombe

Dardalhon¹,

Angelin²,

Baldacci³

et al. 2008

Cell Cycle

View full text Add to dashboard Cite

UVA radiation, the most abundant solar UV radiation reaching Earth's surface, induces oxidative stress through formation of reactive oxygen species (ROS) that can damage different cell components. Because of the broad spectrum of the possible targets of ROS, the cellular response to this radiation is complex. While extensive studies have allowed dissecting the effects of UVB, UVC and gamma radiations on cell cycle progression, few studies have dealt with the effect of UVA so far. Here we use Schizosaccharomyces pombe as a model organism to study biological effects of UVA radiation in living organisms. Through analysis of cell cycle progression in different mutant backgrounds we demonstrate that UVA delays cell cycle progression in G 2 cells in a dose dependent manner. However, despite Chk1 phosphorylation and in contrast to treatments with others genotoxic agents, this cell cycle delay is only partially dependent on DNA integrity checkpoint pathway. We also demonstrate that UVA irradiation of S phase cells slows down DNA replication in a checkpoint independent manner, activates Chk1 to prevent entry into abnormal mitosis and induces formation of Rad22 (homologue to human Rad52) foci. This indicates that DNA structure integrity is challenged. Furthermore, the cell cycle delay observed in checkpoint mutants exposed to UVA is not abolished when stress response pathway is inactivated or when down regulation of protein synthesis is prevented. In conclusion, fission yeast is a useful model to dissect the fundamental molecular mechanisms involved in UVA response that may contribute to skin cancer and aging.

show abstract

Section: Resultsmentioning

confidence: 99%

Unconventional effects of UVA radiation on cell cycle progression inS. pombe

Dardalhon¹,

Angelin²,

Baldacci³

et al. 2008

Cell Cycle

View full text Add to dashboard Cite

show abstract

“…Accordingly, we found that Egrad9 messenger RNA is expressed in PSc, IGL, and FGL, and established the nuclear location of these transcripts in all cells of protoscoleces. It was demonstrated that cells with altered Rad9 expression are sensitive to DNA damage (Hang et al, 2000; Hopkins et al, 2004; Dang et al, 2005) and defective in aspects of cell cycle checkpoint control (Hirai and Wang, 2002; Hopkins et al, 2004) all along the evolutionary tree. These results suggest that the presence of EgRAD9 in FGL and in PSc of E. granulosus is related to the survival of the parasite.…”

Section: Discussionmentioning

confidence: 99%

DNA damage, RAD9 and fertility/infertility of Echinococcus granulosus hydatid cysts

Cabrera

Cabrejos²,

Morassutti

et al. 2008

Journal Cellular Physiology

View full text Add to dashboard Cite

Hydatidosis, caused by the larval stage of the platyhelminth parasite Echinococcus granulosus, affects human and animal health. Hydatid fertile cysts are formed in intermediate hosts (human and herbivores) producing protoscoleces, the infective form to canines, at their germinal layers. Infertile cysts are also formed, but they are unable to produce protoscoleces. The molecular mechanisms involved in hydatid cysts fertility/infertility are unknown. Nevertheless, previous work from our laboratory has suggested that apoptosis is involved in hydatid cyst infertility and death. On the other hand, fertile hydatid cysts can resist oxidative damage due to reactive oxygen and nitrogen species. On these foundations, we have postulated that when oxidative damage of DNA in the germinal layers exceeds the capability of DNA repair mechanisms, apoptosis is triggered and hydatid cysts infertility occurs. We describe a much higher percentage of nuclei with oxidative DNA damage in dead protoscoleces and in the germinal layer of infertile cysts than in fertile cysts, suggesting that DNA repair mechanisms are active in fertile cysts. rad9, a conserved gene, plays a key role in cell cycle checkpoint modulation and DNA repair. We found that RAD9 of E. granulosus (EgRAD9) is expressed at the mRNA and protein levels. As it was found in other eukaryotes, EgRAD9 is hyperphosphorylated in response to DNA damage. Our results suggest that molecules involved in DNA repair in the germinal layer of fertile hydatid cysts and in protoscoleces, such as EgRAD9, may allow preserving the fertility of hydatid cysts in the presence of ROS and RNS.

show abstract

“…This was demonstrated by using asynchronously dividing cells, as well as by monitoring populations pulse-labeled with BrdU. Interestingly, S. pombe rad9 null cells are completely unable to delay cycling in G 2 after ionizing radiation exposure (2, 65) but two different point mutants can initiate yet fail to maintain the delays for the same period as in rad9 ϩ cells (31). This raises the possibility that at least one function of Mrad9 in ionizing-radiation-induced G 2 checkpoint control in mammals is to maintain a cycling delay and that other proteins are responsible for the initiation of this checkpoint.…”

Section: Discussionmentioning

confidence: 99%

“…NEO flanked with FRT sites was inserted into the intron. This deletion is predicted to generate a null mutation, based on previous studies with human and fission yeast orthologs indicating the biological significance of this region (31,42,43). Singly targeted cells (see Materials and Methods) were expanded and then treated with a higher concentration of G418 to select for homozygous targeted cells.…”

Section: Methodsmentioning

confidence: 99%

Deletion of Mouse Rad9 Causes Abnormal Cellular Responses to DNA Damage, Genomic Instability, and Embryonic Lethality

Hopkins

Auerbach

Wang

et al. 2004

Molecular and Cellular Biology

110

163

View full text Add to dashboard Cite

The fission yeast Schizosaccharomyces pombe rad9 gene promotes cell survival through activation of cell cycle checkpoints induced by DNA damage. Mouse embryonic stem cells with a targeted deletion of Mrad9, the mouse ortholog of this gene, were created to evaluate its function in mammals. Mrad9؊/؊ cells demonstrated a marked increase in spontaneous chromosome aberrations and HPRT mutations, indicating a role in the maintenance of genomic integrity. These cells were also extremely sensitive to UV light, gamma rays, and hydroxyurea, and heterozygotes were somewhat sensitive to the last two agents relative to Mrad9 ؉/؉ controls. Mrad9 ؊/؊ cells could initiate but not maintain gamma-ray-induced G 2 delay and retained the ability to delay DNA synthesis rapidly after UV irradiation, suggesting that checkpoint abnormalities contribute little to the radiosensitivity observed. Ectopic expression of Mrad9 or human HRAD9 complemented Mrad9 ؊/؊ cell defects, indicating that the gene has radioresponse and genomic maintenance functions that are evolutionarily conserved. Mrad9 ؉/؊ mice were generated, but heterozygous intercrosses failed to yield Mrad9 ؊/؊ pups, since embryos died at midgestation. Furthermore, Mrad9 ؊/؊ mouse embryo fibroblasts were not viable. These investigations establish Mrad9 as a key mammalian genetic element of pathways that regulate the cellular response to DNA damage, maintenance of genomic integrity, and proper embryonic development.

show abstract

Mutant alleles of Schizosaccharomyces pombe rad9+ alter hydroxyurea resistance, radioresistance and checkpoint control

Cited by 9 publications

References 45 publications

Unconventional effects of UVA radiation on cell cycle progression inS. pombe

Unconventional effects of UVA radiation on cell cycle progression inS. pombe

DNA damage, RAD9 and fertility/infertility of Echinococcus granulosus hydatid cysts

Deletion of Mouse Rad9 Causes Abnormal Cellular Responses to DNA Damage, Genomic Instability, and Embryonic Lethality

Contact Info

Product

Resources

About