scholarly journals Modulation of Cell Cycle–specific Gene Expressions at the Onset of S Phase Arrest Contributes to the Robust DNA Replication Checkpoint Response in Fission Yeas

2007 ◽  
Vol 18 (5) ◽  
pp. 1756-1767 ◽  
Author(s):  
Zhaoqing Chu ◽  
Juntao Li ◽  
Majid Eshaghi ◽  
Xu Peng ◽  
R. Krishna M. Karuturi ◽  
...  

Fission yeast replication checkpoint kinases Rad3p and Cds1p are essential for maintaining cell viability after transient treatment with hydroxyurea (HU), an agent that blocks DNA replication. Although current studies have focused on the cyclin-dependent protein kinase Cdc2p that is regulated by these checkpoint kinases, other aspects of their functions at the onset of S phase arrest have not been fully understood. In this study, we use genome-wide DNA microarray analyses to show that HU-induced change of expression profiles in synchronized G2 cells occurs specifically at the onset of S phase arrest. Induction of many core environmental stress response genes and repression of ribosomal genes happen during S phase arrest. Significantly, peak expression level of the MluI-like cell cycle box (MCB)-cluster (G1) genes is maintained at the onset of S phase arrest in a Rad3p- and Cds1p-dependent manner. Expression level maintenance of the MCB-cluster is mediated through the accumulation of Rep2p, a putative transcriptional activator of the MBF complex. Conversely, the FKH-cluster (M) genes are repressed during the onset of S phase arrest in a Rad3p-dependent manner. Repression of the FKH-cluster genes is mediated through the decreased levels of one of the putative forkhead transcription factors, Sep1p, but not Fkh2p. Together, our results demonstrate that Rad3p and Cds1p modulate transcriptional response during the onset of S phase arrest.

1999 ◽  
Vol 112 (6) ◽  
pp. 927-937 ◽  
Author(s):  
S.W. Wang ◽  
C. Norbury ◽  
A.L. Harris ◽  
T. Toda

The replication checkpoint (or ‘S-M checkpoint’) control prevents progression into mitosis when DNA replication is incomplete. Caffeine has been known for some time to have the capacity to override the S-M checkpoint in animal cells. We show here that caffeine also disrupts the S-M checkpoint in the fission yeast Schizosaccharomyces pombe. By contrast, no comparable effects of caffeine on the S. pombe DNA damage checkpoint were seen. S. pombe cells arrested in early S phase and then exposed to caffeine lost viability rapidly as they attempted to enter mitosis, which was accompanied by tyrosine dephosphorylation of Cdc2. Despite this, the caffeine-induced loss of viability was not blocked in a temperature-sensitive cdc2 mutant incubated at the restrictive temperature, although catastrophic mitosis was prevented under these conditions. This suggests that, in addition to S-M checkpoint control, a caffeine-sensitive function may be important for maintenance of cell viability during S phase arrest. The lethality of a combination of caffeine with the DNA replication inhibitor hydroxyurea was suppressed by overexpression of Cds1 or Chk1, protein kinases previously implicated in S-M checkpoint control and recovery from S phase arrest. In addition, the same combination of drugs was specifically tolerated in cells overexpressing either of two novel S. pombe genes isolated in a cDNA library screen. These findings should allow further molecular investigation of the regulation of S phase arrest, and may provide a useful system with which to identify novel drugs that specifically abrogate the checkpoint control.


Toxins ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 397 ◽  
Author(s):  
Ji Wang ◽  
Haisi Xiao ◽  
Yuanyuan Zhu ◽  
Shuiping Liu ◽  
Zhihang Yuan ◽  
...  

The presence of tannic acid (TA), which is widely distributed in plants, limits the utilization of non-grain feed. Illustrating the toxicity mechanism of TA in animals is important for preventing poisoning and for clinical development of TA. The aim of the present study was to evaluate the toxic effects and possible action mechanism of TA in porcine intestinal IPEC-J2 cells, as well as cell proliferation, apoptosis, and cell cycle. We investigated the toxic effects of TA in IPEC-J2 cells combining the analysis of TA-induced apoptotic responses and effect on the cell cycle. The results revealed that TA is highly toxic to IPEC-J2 cells. The stress-inducible factors reactive oxygen species, malondialdehyde, and 8-hydroxy-2′-deoxyguanosine were increased in response to TA. Furthermore, TA suppressed mitochondrial membrane potential, reduced adenosine triphosphate production, and adversely affected B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein, caspase-9, caspase-3, cytochrome c, cyclin A, cyclin-dependent kinases, ataxia-telangiectasia mutated, and P53 expression in a dose-dependent manner. We suggest that TA induces the mitochondrial pathway of apoptosis and S phase arrest in IPEC-J2 cells.


2008 ◽  
Vol 36 (04) ◽  
pp. 805-813 ◽  
Author(s):  
Ping Shi ◽  
Zhiwei Huang ◽  
Guichen Chen

Rhein, an anthraquinone derivative of rhubarb, inhibits the proliferation of various human cancer cells. In this paper, we focused on studying the effects of rhein on human hepatocelluar carcinoma BEL-7402 cells and further understanding the underlying molecular mechanism in an effort to make the potential development of rhein in the treatment of cancers. Using MTT assay and flow cytometry, we demonstrate a critical role of rhein in the suppression of BEL-7402 cell proliferation in a concentration- and time-dependent manner. The increase of apoptosis rate was observed after incubation of BEL-7402 cells with rhein at 50–200 μM for 48 hours, and the cells exhibit typical apoptotic features including cellular morphological change and chromatin condensation. Moreover, rhein-induced cell cycle S-phase arrest. Additionally, after rhein treatment, expression levels of c-Myc gene were decreased, while those of caspase-3 gene were increased in a dose-dependent manner by using real-time PCR assay. The results demonstrate for the first time that cell cycle S-phase arrest is one of the mechanisms of rhein in inhibition of BEL-7402 cells. Rhein plays its role by inducing cell cycle arrest via downregulation of oncogene c-Myc and apoptosis through the caspase-dependent pathway. It is expected that rhein will be effective and useful as a new agent in hepatocelluar carcinoma treatment in the future.


Life Sciences ◽  
2008 ◽  
Vol 83 (9-10) ◽  
pp. 346-355 ◽  
Author(s):  
Yong Hwan Han ◽  
Suhn Hee Kim ◽  
Sung Zoo Kim ◽  
Woo Hyun Park

Oncotarget ◽  
2017 ◽  
Vol 8 (55) ◽  
pp. 94286-94296 ◽  
Author(s):  
Ming Han ◽  
Xin Cheng ◽  
Zhiqin Gao ◽  
Rongrong Zhao ◽  
Shizhuang Zhang

2001 ◽  
Vol 21 (4) ◽  
pp. 1196-1206 ◽  
Author(s):  
Susannah L. Green ◽  
Rachel A. Freiberg ◽  
Amato J. Giaccia

ABSTRACT We investigated the role of the cyclin-dependent kinase inhibitors p21Cip1 and p27Kip1 in cell cycle regulation during hypoxia and reoxygenation. While moderate hypoxia (1 or 0.1% oxygen) does not significantly impair bromodeoxyuridine incorporation, at very low oxygen tensions (0.01% oxygen) DNA replication is rapidly shut down in immortalized mouse embryo fibroblasts. This S-phase arrest is intact in fibroblasts lacking the cyclin kinase inhibitors p21Cip1 and p27Kip1, indicating that these molecules are not essential elements of the arrest pathway. Hypoxia-induced arrest is accompanied by dephosphorylation of pRb and inhibition of cyclin-dependent kinase 2, which results in part from inhibitory phosphorylation. Interestingly, cells lacking the retinoblastoma tumor suppressor protein also display arrest under hypoxia, suggesting that pRb is not an essential mediator of this response. Upon reoxygenation, DNA synthesis resumes by 3.5 h and reaches aerobic levels by 6 h. Cells lacking p21, however, resume DNA synthesis more rapidly upon reoxygenation than wild-type cells, suggesting that this inhibitor may play a role in preventing premature reentry into the cell cycle upon cessation of the hypoxic stress. While p27 null cells did not exhibit rapid reentry into the cell cycle, cells lacking both p21 and p27 entered S phase even more aggressively than those lacking p21 alone, revealing a possible secondary role for p27 in this response. Cdk2 activity is also restored more rapidly in the double-knockout cells when returned to normoxia. These studies reveal that restoration of DNA synthesis after hypoxic stress, but not the S phase arrest itself, is regulated by p21 and p27.


Endocrinology ◽  
1993 ◽  
Vol 133 (5) ◽  
pp. 2403-2406 ◽  
Author(s):  
P Smerdely ◽  
V Pitsiavas ◽  
S C Boyages

PLoS ONE ◽  
2014 ◽  
Vol 9 (6) ◽  
pp. e100004 ◽  
Author(s):  
Laëtitia Trapp-Fragnet ◽  
Djihad Bencherit ◽  
Danièle Chabanne-Vautherot ◽  
Yves Le Vern ◽  
Sylvie Remy ◽  
...  

2009 ◽  
Vol 29 (18) ◽  
pp. 4959-4970 ◽  
Author(s):  
Zhaoqing Chu ◽  
Majid Eshaghi ◽  
Suk Yean Poon ◽  
Jianhua Liu

ABSTRACT Transcription of the MluI cell cycle box (MCB) motif-containing genes at G1 phase is regulated by the MCB-binding factors (MBF) (also called DSC1) in Schizosaccharomyces pombe. Upon S-phase arrest, the MBF transcriptional activity is induced through the accumulation of the MBF activator Rep2. In this study, we show that the turnover of Rep2 is attributable to ubiquitin-mediated proteolysis. Levels of Rep2 oscillate during the cell cycle, with a peak at G1 phase, coincident with the MBF activity. Furthermore, we show that Rep2 ubiquitination requires the function of the E3 ligase anaphase-promoting complex/cyclosome (APC/C). Ste9 can be phosphorylated by the checkpoint kinase Cds1 in vitro, and its inhibition/phosphorylation at S-phase arrest is dependent on the function of Cds1. Our data indicate that the Cds1-dependent stabilization of Rep2 is achieved through the inhibition/phosphorylation of APC/C-Ste9 at the onset of S-phase arrest. Stabilization of Rep2 is important for stimulating transcription of the MBF-dependent genes to ensure a sufficient supply of proteins essential for cell recovery from S-phase arrest. We propose that oscillation of Rep2 plays a role in regulation of periodic transcription of the MBF-dependent genes during cell cycle progression.


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