Regulation of Septum Formation in Aspergillus nidulans by a DNA Damage Checkpoint Pathway

Genetics ◽  
1998 ◽  
Vol 148 (3) ◽  
pp. 1055-1067
Author(s):  
Steven D Harris ◽  
Peter R Kraus
Keyword(s):  
Dna Damage ◽  
Aspergillus Nidulans ◽  
Cellular Response ◽  
Dna Damage Checkpoint ◽  
Temperature Sensitive ◽  
Dna Metabolism ◽  
Chromosomal Dna ◽  
Checkpoint Response ◽  
Septum Formation ◽  
Checkpoint Pathway

Abstract In Aspergillus nidulans, germinating conidia undergo multiple rounds of nuclear division before the formation of the first septum. Previous characterization of temperature-sensitive sepB and sepJ mutations showed that although they block septation, they also cause moderate defects in chromosomal DNA metabolism. Results presented here demonstrate that a variety of other perturbations of chromosomal DNA metabolism also delay septum formation, suggesting that this is a general cellular response to the presence of sublethal DNA damage. Genetic evidence is provided that suggests that high levels of cyclin-dependent kinase (cdk) activity are required for septation in A. nidulans. Consistent with this notion, the inhibition of septum formation triggered by defects in chromosomal DNA metabolism depends upon Tyr-15 phosphorylation of the mitotic cdk p34nimX. Moreover, this response also requires elements of the DNA damage checkpoint pathway. A model is proposed that suggests that the DNA damage checkpoint response represents one of multiple sensory inputs that modulates p34nimX activity to control the timing of septum formation.

Replication Protein A phosphorylation and the cellular response to DNA damage

DNA Repair ◽  
2004 ◽  
Vol 3 (8-9) ◽  
pp. 1015-1024 ◽  
Author(s):  
Sara K. Binz ◽  
Anne M. Sheehan ◽  
Marc S. Wold
Keyword(s):  
Dna Damage ◽  
Cellular Response ◽  
Protein A ◽  
Replication Protein A ◽  
Replication Protein

scholarly journals mtCLIC/CLIC4, an Organellular Chloride Channel Protein, Is Increased by DNA Damage and Participates in the Apoptotic Response to p53

2002 ◽  
Vol 22 (11) ◽  
pp. 3610-3620 ◽  
Author(s):  
Ester Fernández-Salas ◽  
Kwang S. Suh ◽  
Vladislav V. Speransky ◽  
Wendy L. Bowers ◽  
Joshua M. Levy ◽  
...  
Keyword(s):  
Dna Damage ◽  
Chloride Channel ◽  
Chloride Channels ◽  
Mitochondrial Membrane ◽  
Cellular Response ◽  
Mitochondrial Protein ◽  
Inner Mitochondrial Membrane ◽  
Necrosis Factor Alpha ◽  
Channel Protein ◽  
Factor Alpha

ABSTRACT mtCLIC/CLIC4 (referred to here as mtCLIC) is a p53- and tumor necrosis factor alpha-regulated cytoplasmic and mitochondrial protein that belongs to the CLIC family of intracellular chloride channels. mtCLIC associates with the inner mitochondrial membrane. Dual regulation of mtCLIC by two stress response pathways suggested that this chloride channel protein might contribute to the cellular response to cytotoxic stimuli. DNA damage or overexpression of p53 upregulates mtCLIC and induces apoptosis. Overexpression of mtCLIC by transient transfection reduces mitochondrial membrane potential, releases cytochrome c into the cytoplasm, activates caspases, and induces apoptosis. mtCLIC is additive with Bax in inducing apoptosis without a physical association of the two proteins. Antisense mtCLIC prevents the increase in mtCLIC levels and reduces apoptosis induced by p53 but not apoptosis induced by Bax, suggesting that the two proapoptotic proteins function through independent pathways. Our studies indicate that mtCLIC, like Bax, Noxa, p53AIP1, and PUMA, participates in a stress-induced death pathway converging on mitochondria and should be considered a target for cancer therapy through genetic or pharmacologic approaches.

Mutagenesis and More: umuDC and the Escherichia coli SOS Response

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1599-1610 ◽  
Author(s):  
Bradley T Smith ◽  
Graham C Walker
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Cellular Response ◽  
Sos Response ◽  
Posttranslational Regulation ◽  
E Coli ◽  
Sos Mutagenesis ◽  
Induced Mutagenesis ◽  
Mechanistic Basis ◽  
Increase Cell Survival

Abstract The cellular response to DNA damage that has been most extensively studied is the SOS response of Escherichia coli. Analyses of the SOS response have led to new insights into the transcriptional and posttranslational regulation of processes that increase cell survival after DNA damage as well as insights into DNA-damage-induced mutagenesis, i.e., SOS mutagenesis. SOS mutagenesis requires the recA and umuDC gene products and has as its mechanistic basis the alteration of DNA polymerase III such that it becomes capable of replicating DNA containing miscoding and noncoding lesions. Ongoing investigations of the mechanisms underlying SOS mutagenesis, as well as recent observations suggesting that the umuDC operon may have a role in the regulation of the E. coli cell cycle after DNA damage has occurred, are discussed.

scholarly journals Veliparib Is an Effective Radiosensitizing Agent in a Preclinical Model of Medulloblastoma

2021 ◽  
Vol 8 ◽  
Author(s):  
Jessica Buck ◽  
Patrick J. C. Dyer ◽  
Hilary Hii ◽  
Brooke Carline ◽  
Mani Kuchibhotla ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Combination Therapy ◽  
Cellular Response ◽  
Molecular Subtype ◽  
Parp Inhibitor ◽  
Single Agent ◽  
Parp Inhibition ◽  
Preclinical Model ◽  
Radiation Induced

Medulloblastoma is the most common malignant childhood brain tumor, and 5-year overall survival rates are as low as 40% depending on molecular subtype, with new therapies critically important. As radiotherapy and chemotherapy act through the induction of DNA damage, the sensitization of cancer cells through the inhibition of DNA damage repair pathways is a potential therapeutic strategy. The poly-(ADP-ribose) polymerase (PARP) inhibitor veliparib was assessed for its ability to augment the cellular response to radiation-induced DNA damage in human medulloblastoma cells. DNA repair following irradiation was assessed using the alkaline comet assay, with veliparib inhibiting the rate of DNA repair. Veliparib treatment also increased the number of γH2AX foci in cells treated with radiation, and analysis of downstream pathways indicated persistent activation of the DNA damage response pathway. Clonogenicity assays demonstrated that veliparib effectively inhibited the colony-forming capacity of medulloblastoma cells, both as a single agent and in combination with irradiation. These data were then validated in vivo using an orthotopic implant model of medulloblastoma. Mice harboring intracranial D425 medulloblastoma xenografts were treated with vehicle, veliparib, 18 Gy multifractionated craniospinal irradiation (CSI), or veliparib combined with 18 Gy CSI. Animals treated with combination therapy exhibited reduced tumor growth rates concomitant with increased intra-tumoral apoptosis observed by immunohistochemistry. Kaplan–Meier analyses revealed a statistically significant increase in survival with combination therapy compared to CSI alone. In summary, PARP inhibition enhanced radiation-induced cytotoxicity of medulloblastoma cells; thus, veliparib or other brain-penetrant PARP inhibitors are potential radiosensitizing agents for the treatment of medulloblastoma.

scholarly journals hSSB2 (NABP1) is required for the recruitment of RPA during the cellular response to DNA UV damage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Didier Boucher ◽  
Ruvini Kariawasam ◽  
Joshua Burgess ◽  
Adrian Gimenez ◽  
Tristan E. Ocampo ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cellular Response ◽  
Excision Repair ◽  
Protein A ◽  
Ultraviolet B ◽  
Repair System ◽  
Uvb Radiation ◽  
Exogenous Dna

AbstractMaintenance of genomic stability is critical to prevent diseases such as cancer. As such, eukaryotic cells have multiple pathways to efficiently detect, signal and repair DNA damage. One common form of exogenous DNA damage comes from ultraviolet B (UVB) radiation. UVB generates cyclobutane pyrimidine dimers (CPD) that must be rapidly detected and repaired to maintain the genetic code. The nucleotide excision repair (NER) pathway is the main repair system for this type of DNA damage. Here, we determined the role of the human Single-Stranded DNA Binding protein 2, hSSB2, in the response to UVB exposure. We demonstrate that hSSB2 levels increase in vitro and in vivo after UVB irradiation and that hSSB2 rapidly binds to chromatin. Depletion of hSSB2 results in significantly decreased Replication Protein A (RPA32) phosphorylation and impaired RPA32 localisation to the site of UV-induced DNA damage. Delayed recruitment of NER protein Xeroderma Pigmentosum group C (XPC) was also observed, leading to increased cellular sensitivity to UVB. Finally, hSSB2 was shown to have affinity for single-strand DNA containing a single CPD and for duplex DNA with a two-base mismatch mimicking a CPD moiety. Altogether our data demonstrate that hSSB2 is involved in the cellular response to UV exposure.

scholarly journals Histone H3 and H4 Ubiquitylation by the CUL4-DDB-ROC1 Ubiquitin Ligase Facilitates Cellular Response to DNA Damage

2006 ◽  
Vol 22 (3) ◽  
pp. 383-394 ◽  
Author(s):  
Hengbin Wang ◽  
Ling Zhai ◽  
Jun Xu ◽  
Heui-Yun Joo ◽  
Sarah Jackson ◽  
...  
Keyword(s):  
Dna Damage ◽  
Ubiquitin Ligase ◽  
Cellular Response ◽  
Histone H3

scholarly journals Cellular response to DNA damage is enhanced by the pR plasmid in mouse cells and in Escherichia coli.

1986 ◽  
Vol 6 (2) ◽  
pp. 586-592 ◽  
Author(s):  
L Marcucci ◽  
F Gigliani ◽  
P A Battaglia ◽  
R Bosi ◽  
E Sporeno ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Statistical Analysis ◽  
Cellular Response ◽  
Regulatory Mechanism ◽  
Uv Light ◽  
Transformed Cells ◽  
Insertion Mutagenesis ◽  
Mouse Cells ◽  
Inducible Repair

The pR plasmid, which enhances the survival of Escherichia coli C600 exposed to UV light by induction of the SOS regulatory mechanism, showed the same effect when it transformed mouse LTA cells (tk-, aprt-). With Tn5 insertion mutagenesis which inactivates UV functions in the pR plasmid, we recognized two different regions of the plasmid, uvp1 and uvp2. These pR UVR- mutants exhibited the same effect in LTA transformed cells, demonstrating that resistance to UV light, carried by the pR plasmid, was really due to the expression of these two regions, which were also in the mouse cells. Statistical analysis showed that the expression of the uvp1 and uvp2 regions significantly increased (P less than 0.01) the survival upon exposure to UV light in mouse cells and bacteria. These results might suggest the presence of an inducible repair response to DNA damage in mouse LTA cells.

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