scholarly journals Tof1p Regulates DNA Damage Responses During S Phase in Saccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 157 (2) ◽  
pp. 567-577 ◽  
Author(s):  
Eric J Foss
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Double Mutant ◽  
S Phase ◽  
Damage Response ◽  
Dna Damage Responses ◽  
Dna Damage Response Pathway

Abstract A tof1 mutant was recovered in a screen aimed at identifying genes involved specifically in the S phase branch of the MEC1-dependent DNA damage response pathway. The screen was based on the observation that mutants missing this branch are particularly dependent on the cell cycle-wide branch and, therefore, on RAD9, for surviving DNA damage. tof1 and rad9 conferred synergistic sensitivity to MMS, UV, and HU, and the double mutant was incapable of slowing S phase in response to MMS, inducing RNR3 transcription in response to UV, and phosphorylating Rad53p in response to HU. TOF1's contribution to DNA damage response appeared to be restricted to S phase, since TOF1 did not contribute to UV-induced transcription during G1 or to the cdc13-1-induced block to anaphase in G2/M. I suggest a model in which Tof1p functions to link Mec1p with Rad53p.

scholarly journals Dysregulation of hsa-miR-34a and hsa-miR-449a leads to overexpression of PACS-1 and loss of DNA damage response (DDR) in cervical cancer

2020 ◽  
Vol 295 (50) ◽  
pp. 17169-17186
Author(s):  
Mysore S. Veena ◽  
Santanu Raychaudhuri ◽  
Saroj K. Basak ◽  
Natarajan Venkatesan ◽  
Parameet Kumar ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Dna Damage ◽  
Cell Growth ◽  
Cell Lines ◽  
Cancer Cell ◽  
Dna Damage Response ◽  
S Phase ◽  
Cervical Cancer Cell ◽  
Damage Response

We have observed overexpression of PACS-1, a cytosolic sorting protein in primary cervical tumors. Absence of exonic mutations and overexpression at the RNA level suggested a transcriptional and/or posttranscriptional regulation. University of California Santa Cruz genome browser analysis of PACS-1 micro RNAs (miR), revealed two 8-base target sequences at the 3′ terminus for hsa-miR-34a and hsa-miR-449a. Quantitative RT-PCR and Northern blotting studies showed reduced or loss of expression of the two microRNAs in cervical cancer cell lines and primary tumors, indicating dysregulation of these two microRNAs in cervical cancer. Loss of PACS-1 with siRNA or exogenous expression of hsa-miR-34a or hsa-miR-449a in HeLa and SiHa cervical cancer cell lines resulted in DNA damage response, S-phase cell cycle arrest, and reduction in cell growth. Furthermore, the siRNA studies showed that loss of PACS-1 expression was accompanied by increased nuclear γH2AX expression, Lys382-p53 acetylation, and genomic instability. PACS-1 re-expression through LNA-hsa-anti-miR-34a or -449a or through PACS-1 cDNA transfection led to the reversal of DNA damage response and restoration of cell growth. Release of cells post 24-h serum starvation showed PACS-1 nuclear localization at G1-S phase of the cell cycle. Our results therefore indicate that the loss of hsa-miR-34a and hsa-miR-449a expression in cervical cancer leads to overexpression of PACS-1 and suppression of DNA damage response, resulting in the development of chemo-resistant tumors.

Involvement of Death-Associated Protein Kinases In DNA Damage Responses of B-ALL Cells.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3369-3369
Author(s):  
Magali Humbert ◽  
Michaela Medova ◽  
Barbara Geering ◽  
Wieslawa Blank-Liss ◽  
Hans-Uwe Simon ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Repair ◽  
Gamma Irradiation ◽  
Protein Kinases ◽  
Dna Damage Response ◽  
Lymphoblastic Leukemia ◽  
Damage Response ◽  
Dna Damage Responses

Abstract Abstract 3369 Intact DNA damage response pathways are important for genomic fidelity of cells in order to avoid tumor formation. On the other hand, inhibition of DNA repair provides an important mechanism to enhance the therapeutic efficacy of DNA damaging agents such as gamma-irradiation. Thus, it is important to identify novel players in DNA damage response that might represent novel targets for combination therapies. Death-associated protein kinases (DAPK) are serine/threonine kinases believed to be involved in cell death and autophagy mechanisms, whereby particularly the role of DAPK1 has previously been investigated. The DAPK family is composed of five members: DAPK1, DAPK2 (or DRP-1), DAPK3 (or ZIP kinase), DRAK1 and DRAK2. DAPK1 and DAPK2 share 80% homology in the catalytic domain. Generally, the role of DAPK in DNA damage responses is not well studied. To analyze the role of DAPK1 and DAPK2 in response to gamma-irradiation, we used p53 wild-type REH B-cell acute lymphoblastic leukemia (B-ALL) cells as a model. In response to irradiation, DAPK1 protein expression increased paralleled by an increased of total p53, phospho-Ser20-p53 and p21WAF1/CIP1. DAPK2 expression, however, did not increase. Since upregulation of p21WAF1/CIP1, a classical p53 target in response to DNA damage leads to cell cycle arrest, we asked whether knocking down DAPK1 or DAPK2 might affect the cell cycle. Interestingly, knocking down DAPK2 but not DAPK1 led to a significant increase of S-phase cells upon irradiation. Moreover, knocking down DAPK2 attenuated the induction of DAPK1 upon irradiation indicating a DAPK2-DAPK1 cascade in DNA damage responses. Next, given the significant role of p21WAF1/CIP1 and p53 in DNA damage responses, we tested if DAPK2 might directly participate in a novel signaling pathway by interacting with these proteins. Indeed, pull down assays revealed that p21WAF1/CIP1 and p53 are novel DAPK2 interacting proteins. Clearly, further experiments are needed to define the DAPK2-DAPK1-p53- p21WAF1/CIP1 network in DNA repair pathways. In conclusion, we identified a novel role for DAPK1 and DAPK2 in DNA damage responses of B-ALL cells and propose a novel DAPK2/DAPK1/p53/ p21WAF1/CIP1 DNA damage regulatory pathway. Disclosures: No relevant conflicts of interest to declare.

A Role for NIPA in DNA Damage Response.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1265-1265
Author(s):  
Christine von Klitzing ◽  
Florian Bassermann ◽  
Stephan W. Morris ◽  
Christian Peschel ◽  
Justus Duyster
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Phosphorylation Site ◽  
Genotoxic Stress ◽  
S Phase ◽  
Damage Response ◽  
A Cell ◽  
Cycle Dependent

Abstract The nuclear interaction partner of ALK (NIPA) is a nuclear protein identified by our group in a screen for NPM-ALK interaction partners. We recently reported that NIPA is an F-box protein that assembles with SKP1, Cul1 and Roc1 to establish a novel SCF-type E3 ubiquitin ligase. The formation of the SCFNIPA complex is regulated by cell cycle-dependent phosphorylation of NIPA that restricts SCFNIPA assembly from G1- to late S-phase, thus allowing its substrates to be active from late S-phase throughout mitosis. Proteins involved in cell cycle regulation frequently play a role in DNA damage checkpoints. We therefore sought to determine whether NIPA has a function in the cellular response to genotoxic stress. For this reason we treated NIH/3T3 cells with various DNA-damaging agents. Surprisingly, we observed phosphorylation of NIPA in response to some of these agents, including UV radiation. This phosphorylation was cell cycle phase independent and thus independent of the physiological cell cycle dependent phosphorylation of NIPA. The relevant phosphorylation site is identical to the respective site in the course of cell cycle-dependent phosphorylation of NIPA. Thus, phosphorylation of NIPA upon genotoxic stress would inactivate the SCFNIPA complex in a cell cycle independent manner. Interestingly, this phosphorylation site lies within a consensus site of the Chk1/Chk2 checkpoint kinases. These kinases are central to DNA damage checkpoint signaling. Chk1 is activated by ATR in response to blocked replication forks as they occur after treatment with UV. We performed experiments using the ATM/ATR inhibitor caffeine and the Chk1 inhibitor SB218078 to investigate a potential role of Chk1 in NIPA phosphorylation. Indeed, we found both inhibitors to prevent UV-induced phosphorylation of NIPA. Current experiments applying Chk1 knock-out cells will unravel the role of Chk1 in NIPA phosphorylation. Additional experiments were performed to investigate a function for NIPA in DNA-damage induced apoptosis. In this regard, we observed overexpression of NIPA WT to induce apoptosis in response to UV, whereas no proapoptotic effect was seen with the phosphorylation deficient NIPA mutant. Therefore, the phosphorylated form of NIPA may be involved in apoptotic signaling pathways. In summary, we present data suggesting a cell cycle independent function for NIPA. This activity is involved in DNA damage response and may be involved in regulating apoptosis upon genotoxic stress.

scholarly journals Banp regulates DNA damage response and chromosome segregation during the cell cycle in zebrafish retina

2021 ◽  
Author(s):  
Swathy Babu ◽  
Yuki Takeuchi ◽  
Ichiro Masai
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Replication ◽  
Dna Damage Response ◽  
Chromosome Segregation ◽  
Cell Cycle Progression ◽  
Target Genes ◽  
Damage Response ◽  
Dna Damage Responses

Btg3-associated nuclear protein (Banp) was originally identified as a nuclear matrix-associated protein and it functions as a tumor suppressor. At molecular level, Banp regulates transcription of metabolic genes via a CGCG-containing motif called the Banp motif. However, its physiological roles in embryonic development are unknown. Here we report that Banp is indispensable for DNA damage response and chromosome segregation during mitosis. Zebrafish banp mutants show mitotic arrest and apoptosis in developing retina. We found that DNA replication stress and tp53-dependent DNA damage responses were activated to induce apoptosis in banp mutants, suggesting that Banp is required for integrity of DNA replication and DNA damage repair. Furthermore, in banp mutants, chromosome segregation was not smoothly processed from prometaphase to anaphase, leading to a prolonged M-phase. Our RNA- and ATAC-sequencing identified 31 candidates for direct Banp target genes that carry the Banp motif. Interestingly, two chromosome segregation regulators, cenpt and ncapg, are included in this list. Thus, Banp directly regulates transcription of cenpt and ncapg to promote chromosome segregation during mitosis. Our findings provide the first in vivo evidence that Banp is required for cell-cycle progression and cell survival by regulating DNA damage responses and chromosome segregation during mitosis.

scholarly journals Lack of CCAAT Enhancer Binding Protein Beta (C/EBPβ) in Uterine Epithelial Cells Impairs Estrogen-Induced DNA Replication, Induces DNA Damage Response Pathways, and Promotes Apoptosis

2010 ◽  
Vol 30 (7) ◽  
pp. 1607-1619 ◽  
Author(s):  
Cyril Ramathal ◽  
Indrani C. Bagchi ◽  
Milan K. Bagchi
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Replication ◽  
Epithelial Cells ◽  
Cell Cycle Arrest ◽  
Dna Damage Response ◽  
S Phase ◽  
Uterine Epithelial Cells ◽  
Cycle Arrest ◽  
Damage Response

ABSTRACT Female mice lacking the transcription factor C/EBPβ are infertile and display markedly reduced estrogen (E)-induced proliferation of the uterine epithelial lining during the reproductive cycle. The present study showed that E-stimulated luminal epithelial cells of a C/EBPβ-null uterus are able to proceed through the G1 phase of the cell cycle before getting arrested in the S phase. This cell cycle arrest was accompanied by markedly reduced levels of expression of E2F3, an E2F family member, and a lack of nuclear localization of cyclin E, a critical regulator of cdk2. An increased nuclear accumulation of p27, an inhibitor of the cyclin E-cdk2 complex, was also observed for the mutant epithelium. Gene expression profiling of C/EBPβ-null uterine epithelial cells revealed that the blockade of E-induced DNA replication triggers the activation of several well-known components of the DNA damage response pathway, such as ATM, ATR, histone H2AX, checkpoint kinase 1, and tumor suppressor p53. The activation of p53 by ATM/ATR kinase led to increased levels of expression of p21, an inhibitor of G1-S-phase progression, which helps maintain cell cycle arrest. Additionally, p53-dependent mechanisms contributed to an increased apoptosis of replication-defective cells in the C/EBPβ-null epithelium. C/EBPβ, therefore, is an essential mediator of E-induced growth and survival of uterine epithelial cells of cycling mice.

scholarly journals ATR- and ATM-Mediated DNA Damage Response Is Dependent on Excision Repair Assembly during G1 but Not in S Phase of Cell Cycle

PLoS ONE ◽  
2016 ◽  
Vol 11 (7) ◽  
pp. e0159344 ◽  
Author(s):  
Alo Ray ◽  
Chessica Blevins ◽  
Gulzar Wani ◽  
Altaf A. Wani
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Excision Repair ◽  
S Phase ◽  
Damage Response

scholarly journals BK Polyomavirus Activates the DNA Damage Response To Prolong S Phase

2019 ◽  
Vol 93 (14) ◽  
Author(s):  
Joshua L. Justice ◽  
Jason M. Needham ◽  
Sunnie R. Thompson
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Damage Response ◽  
S Phase ◽  
Genome Replication ◽  
Viral Production ◽  
Viral Dna ◽  
Bk Polyomavirus ◽  
Damage Response ◽  
Infected Cells

ABSTRACT BK polyomavirus (PyV) is a major source of kidney failure in transplant recipients. The standard treatment for patients with lytic BKPyV infection is to reduce immunosuppressive therapy, which increases the risk of graft rejection. PyVs are DNA viruses that rely upon host replication proteins for viral genome replication. A hallmark of PyV infection is activation of the DNA damage response (DDR) to prevent severe host and viral DNA damage that impairs viral production by an unknown mechanism. Therefore, we sought to better understand why BKPyV activates the DDR through the ATR and ATM pathways and how this prevents DNA damage and leads to increased viral production. When ATR was inhibited in BKPyV-infected primary kidney cells, severe DNA damage occurred due to premature Cdk1 activation, which resulted in mitosis of cells that were actively replicating host DNA in S phase. Conversely, ATM was required for efficient entry into S phase and to prevent normal mitotic entry after G2 phase. The synergistic activation of these DDR kinases promoted and maintained BKPyV-mediated S phase to enhance viral production. In contrast to BKPyV infection, DDR inhibition did not disrupt cell cycle control in uninfected cells. This suggests that DDR inhibitors may be used to specifically target BKPyV-infected cells. IMPORTANCE BK polyomavirus (BKPyV) is an emerging pathogen that reactivates in immunosuppressed organ transplant patients. We wanted to understand why BKPyV-induced activation of the DNA damage response (DDR) enhances viral titers and prevents host DNA damage. Here, we show that the virus activates the DNA damage response in order to keep the infected cells in S phase to replicate the viral DNA. The source of DNA damage was due to actively replicating cells with uncondensed chromosomes entering directly into mitosis when the DDR was inhibited in BKPyV-infected cells. This study clarifies the previously enigmatic role of the DDR during BKPyV infection by demonstrating that the virus activates the DDR to maintain the cells in S phase in order to promote viral replication and that disruption of this cell cycle arrest can lead to catastrophic DNA damage for the host.

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