scholarly journals Direct p53 Transcriptional Repression: In Vivo Analysis of CCAAT-Containing G2/M Promoters

2005 ◽  
Vol 25 (9) ◽  
pp. 3737-3751 ◽  
Author(s):  
Carol Imbriano ◽  
Aymone Gurtner ◽  
Fabienne Cocchiarella ◽  
Silvia Di Agostino ◽  
Valentina Basile ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Transcriptional Repression ◽  
Histone Deacetylases ◽  
Specific Binding ◽  
Cell Cycle Control ◽  
Tetramerization Domain ◽  
Before And After

ABSTRACT In response to DNA damage, p53 activates G1/S blocking and apoptotic genes through sequence-specific binding. p53 also represses genes with no target site, such as those for Cdc2 and cyclin B, key regulators of the G2/M transition. Like most G2/M promoters, they rely on multiple CCAAT boxes activated by NF-Y, whose binding to DNA is temporally regulated during the cell cycle. NF-Y associates with p53 in vitro and in vivo through the αC helix of NF-YC (a subunit of NF-Y) and a region close to the tetramerization domain of p53. Chromatin immunoprecipitation experiments indicated that p53 is associated with cyclin B2, CDC25C, and Cdc2 promoters in vivo before and after DNA damage, requiring DNA-bound NF-Y. Following DNA damage, p53 is rapidly acetylated at K320 and K373 to K382, histones are deacetylated, and the release of PCAF and p300 correlates with the recruitment of histone deacetylases (HDACs)—HDAC1 before HDAC4 and HDAC5—and promoter repression. HDAC recruitment requires intact NF-Y binding sites. In transfection assays, PCAF represses cyclin B2, and a nonacetylated p53 mutant shows a complete loss of repression potential, despite its abilities to bind NF-Y and to be recruited on G2/M promoters. These data (i) detail a strategy of direct p53 repression through associations with multiple NF-Y trimers that is independent of sequence-specific binding of p53 and that requires C-terminal acetylation, (ii) suggest that p53 is a DNA damage sentinel of the G2/M transition, and (iii) delineate a new role for PCAF in cell cycle control.

scholarly journals Interchangeable Roles for E2F Transcriptional Repression by the Retinoblastoma Protein and p27KIP1–Cyclin-Dependent Kinase Regulation in Cell Cycle Control and Tumor Suppression

2016 ◽  
Vol 37 (2) ◽  
Author(s):  
Michael J. Thwaites ◽  
Matthew J. Cecchini ◽  
Daniel T. Passos ◽  
Ian Welch ◽  
Frederick A. Dick
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Transcriptional Repression ◽  
Cell Cycle Control ◽  
Retinoblastoma Protein ◽  
Level Control ◽  
Mutant Genotype ◽  
Single Mutant ◽  
Cdk Regulation

ABSTRACT The mammalian G1-S phase transition is controlled by the opposing forces of cyclin-dependent kinases (CDK) and the retinoblastoma protein (pRB). Here, we present evidence for systems-level control of cell cycle arrest by pRB-E2F and p27-CDK regulation. By introducing a point mutant allele of pRB that is defective for E2F repression (Rb1 G ) into a p27KIP1 null background (Cdkn1b −/−), both E2F transcriptional repression and CDK regulation are compromised. These double-mutant Rb1 G/G ; Cdkn1b −/− mice are viable and phenocopy Rb1 +/− mice in developing pituitary adenocarcinomas, even though neither single mutant strain is cancer prone. Combined loss of pRB-E2F transcriptional regulation and p27KIP1 leads to defective proliferative control in response to various types of DNA damage. In addition, Rb1 G/G ; Cdkn1b −/− fibroblasts immortalize faster in culture and more frequently than either single mutant genotype. Importantly, the synthetic DNA damage arrest defect caused by Rb1 G/G ; Cdkn1b −/− mutations is evident in the developing intermediate pituitary lobe where tumors ultimately arise. Our work identifies a unique relationship between pRB-E2F and p27-CDK control and offers in vivo evidence that pRB is capable of cell cycle control through E2F-independent effects.

scholarly journals Transcriptional Repression by the Retinoblastoma Protein through the Recruitment of a Histone Methyltransferase

2001 ◽  
Vol 21 (19) ◽  
pp. 6484-6494 ◽  
Author(s):  
Laurence Vandel ◽  
Estelle Nicolas ◽  
Olivier Vaute ◽  
Roger Ferreira ◽  
Slimane Ait-Si-Ali ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Transcriptional Repression ◽  
Histone Deacetylases ◽  
Histone H3 ◽  
Histone Methyltransferase ◽  
S Phase ◽  
E2f Transcription Factor ◽  
Cycle Dependent

ABSTRACT The E2F transcription factor controls the cell cycle-dependent expression of many S-phase-specific genes. Transcriptional repression of these genes in G0 and at the beginning of G1by the retinoblasma protein Rb is crucial for the proper control of cell proliferation. Rb has been proposed to function, at least in part, through the recruitment of histone deacetylases. However, recent results indicate that other chromatin-modifying enzymes are likely to be involved. Here, we show that Rb also interacts with a histone methyltransferase, which specifically methylates K9 of histone H3. The results of coimmunoprecipitation experiments of endogenous or transfected proteins indicate that this histone methyltransferase is the recently described heterochromatin-associated protein Suv39H1. Interestingly, phosphorylation of Rb in vitro as well as in vivo abolished the Rb-Suv39H1 interaction. We also found that Suv39H1 and Rb cooperate to repress E2F activity and that Suv39H1 could be recruited to E2F1 through its interaction with Rb. Taken together, these data indicate that Suv39H1 is involved in transcriptional repression by Rb and suggest an unexpected link between E2F regulation and heterochromatin.

A Novel Camptothecin Derivative 3j Inhibits Nsclc Proliferation Via Induction of Cell Cycle Arrest By Topo I-Mediated DNA Damage

2019 ◽  
Vol 19 (3) ◽  
pp. 365-374 ◽  
Author(s):  
Yang Liu ◽  
Jingyin Zhang ◽  
Shuyun Feng ◽  
Tingli Zhao ◽  
Zhengzheng Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Dna Damage ◽  
Cyclin D ◽  
Dna Relaxation ◽  
Cycle Arrest ◽  
H460 Cell ◽  
H1975 Cell

Objective: The aim of this study is to investigate the inhibitory effect of camptothecin derivative 3j on Non-Small Cell Lung Cancer (NSCLCs) cells and the potential anti-tumor mechanisms. Background: Camptothecin compounds are considered as the third largest natural drugs which are widely investigated in the world and they suffered restriction because of serious toxicity, such as hemorrhagic cystitis and bone marrow suppression. Methods: Using cell proliferation assay and S180 tumor mice model, a series of 20(S)-O-substituted benzoyl 7- ethylcamptothecin compounds were screened and evaluated the antitumor activities in vitro and in vivo. Camptothecin derivative 3j was selected for further study using flow cytometry in NSCLCs cells. Cell cycle related protein cyclin A2, CDK2, cyclin D and cyclin E were detected by Western Blot. Then, computer molecular docking was used to confirm the interaction between 3j and Topo I. Also, DNA relaxation assay and alkaline comet assay were used to investigate the mechanism of 3j on DNA damage. Results: Our results demonstrated that camptothecin derivative 3j showed a greater antitumor effect in eleven 20(S)-O-substituted benzoyl 7-ethylcamptothecin compounds in vitro and in vivo. The IC50 of 3j was 1.54± 0.41 µM lower than irinotecan with an IC50 of 13.86±0.80 µM in NCI-H460 cell, which was reduced by 8 fold. In NCI-H1975 cell, the IC50 of 3j was 1.87±0.23 µM lower than irinotecan (IC50±SD, 5.35±0.38 µM), dropped by 1.8 fold. Flow cytometry analysis revealed that 3j induced significant accumulation in a dose-dependent manner. After 24h of 3j (10 µM) treatment, the percentage of NCI-H460 cell in S-phase significantly increased (to 93.54 ± 4.4%) compared with control cells (31.67 ± 3.4%). Similarly, the percentage of NCI-H1975 cell in Sphase significantly increased (to 83.99 ± 2.4%) compared with control cells (34.45 ± 3.9%) after treatment with 10µM of 3j. Moreover, increased levels of cyclin A2, CDK2, and decreased levels of cyclin D, cyclin E further confirmed that cell cycle arrest was induced by 3j. Furthermore, molecular docking studies suggested that 3j interacted with Topo I-DNA and DNA-relaxation assay simultaneously confirmed that 3j suppressed the activity of Topo I. Research on the mechanism showed that 3j exhibited anti-tumour activity via activating the DNA damage response pathway and suppressing the repair pathway in NSCLC cells. Conclusion: Novel camptothecin derivative 3j has been demonstrated as a promising antitumor agent and remains to be assessed in further studies.

Mitosis-specific phosphorylation of nucleolin by p34cdc2 protein kinase

1990 ◽  
Vol 10 (7) ◽  
pp. 3607-3618
Author(s):  
P Belenguer ◽  
M Caizergues-Ferrer ◽  
J C Labbé ◽  
M Dorée ◽  
F Amalric
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Control ◽  
Nucleolar Organizer ◽  
Serine Phosphorylation ◽  
Nucleolar Organizer Regions ◽  
Rdna Transcription ◽  
Amino Terminal ◽  
Nucleolar Chromatin

Nucleolin is a ubiquitous multifunctional protein involved in preribosome assembly and associated with both nucleolar chromatin in interphase and nucleolar organizer regions on metaphasic chromosomes in mitosis. Extensive nucleolin phosphorylation by a casein kinase (CKII) occurs on serine in growing cells. Here we report that while CKII phosphorylation is achieved in interphase, threonine phosphorylation occurs during mitosis. We provide evidence that this type of in vivo phosphorylation involves a mammalian homolog of the cell cycle control Cdc2 kinase. In vitro M-phase H1 kinase from starfish oocytes phosphorylated threonines in a TPXK motif present nine times in the amino-terminal part of the protein. The same sites which matched the p34cdc2 consensus phosphorylation sequence were used in vivo during mitosis. We propose that successive Cdc2 and CKII phosphorylation could modulate nucleolin function in controlling cell cycle-dependent nucleolar function and organization. Our results, along with previous studies, suggest that while serine phosphorylation is related to nucleolin function in the control of rDNA transcription, threonine phosphorylation is linked to mitotic reorganization of nucleolar chromatin.

scholarly journals The Human Candidate Tumor Suppressor Gene HIC1 Recruits CtBP through a Degenerate GLDLSKK Motif

2002 ◽  
Vol 22 (13) ◽  
pp. 4890-4901 ◽  
Author(s):  
Sophie Deltour ◽  
Sébastien Pinte ◽  
Cateline Guerardel ◽  
Bohdan Wasylyk ◽  
Dominique Leprince
Keyword(s):  
Binding Site ◽  
Transcriptional Repression ◽  
Histone Deacetylases ◽  
Trichostatin A ◽  
Suppressor Gene ◽  
Close Relative ◽  
Consensus Binding Site ◽  
Candidate Tumor Suppressor Gene

ABSTRACT HIC1 (hypermethylated in cancer) and its close relative HRG22 (HIC1-related gene on chromosome 22) encode transcriptional repressors with five C2H2 zinc fingers and an N-terminal BTB/POZ autonomous transcriptional repression domain that is unable to recruit histone deacetylases (HDACs). Alignment of the HIC1 and HRG22 proteins from various species highlighted a perfectly conserved GLDLSKK/R motif highly related to the consensus CtBP interaction motif (PXDLSXK/R), except for the replacement of the virtually invariant proline by a glycine. HIC1 strongly interacts with mCtBP1 both in vivo and in vitro through this conserved GLDLSKK motif, thus extending the CtBP consensus binding site. The BTB/POZ domain does not interact with mCtBP1, but the dimerization of HIC1 through this domain is required for the interaction with mCtBP1. When tethered to DNA by fusion with the Gal4 DNA-binding domain, the HIC1 central region represses transcription through interactions with CtBP in a trichostatin A-sensitive manner. In conclusion, our results demonstrate that HIC1 mediates transcriptional repression by both HDAC-independent and HDAC-dependent mechanisms and show that CtBP is a HIC1 corepressor that is recruited via a variant binding site.

scholarly journals The Rational Design and Biological Mechanisms of Nanoradiosensitizers

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 504 ◽  
Author(s):  
Hainan Sun ◽  
Xiaoling Wang ◽  
Shumei Zhai
Keyword(s):  
Oxidative Stress ◽  
Cell Cycle ◽  
Dna Damage ◽  
Rational Design ◽  
Design Strategies ◽  
Biological Mechanisms ◽  
Normal Tissues ◽  
Current State

Radiotherapy (RT) has been widely used for cancer treatment. However, the intrinsic drawbacks of RT, such as radiotoxicity in normal tissues and tumor radioresistance, promoted the development of radiosensitizers. To date, various kinds of nanoparticles have been found to act as radiosensitizers in cancer radiotherapy. This review focuses on the current state of nanoradiosensitizers, especially the related biological mechanisms, and the key design strategies for generating nanoradiosensitizers. The regulation of oxidative stress, DNA damage, the cell cycle, autophagy and apoptosis by nanoradiosensitizers in vitro and in vivo is highlighted, which may guide the rational design of therapeutics for tumor radiosensitization.

Induction of G1 Cell Cycle Arrest in Human Glioma Cells by Salinomycin Through Triggering ROS-Mediated DNA Damage In Vitro and In Vivo

2016 ◽  
Vol 42 (4) ◽  
pp. 997-1005 ◽  
Author(s):  
Shi-Jun Zhao ◽  
Xian-Jun Wang ◽  
Qing-Jian Wu ◽  
Chao Liu ◽  
Da-Wei Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Glioma Cells ◽  
Human Glioma ◽  
Human Glioma Cells ◽  
Cycle Arrest ◽  
G1 Cell Cycle Arrest

scholarly journals Overexpression of Bcl-w in the Testis Disrupts Spermatogenesis: Revelation of a Role of BCL-W in Male Germ Cell Cycle Control

2003 ◽  
Vol 17 (9) ◽  
pp. 1868-1879 ◽  
Author(s):  
Wei Yan ◽  
Jun-Xing Huang ◽  
Anna-Stina Lax ◽  
Lauri Pelliniemi ◽  
Eeva Salminen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Germ Cell ◽  
Sertoli Cell ◽  
Germ Cells ◽  
Cell Cycle Progression ◽  
Cell Cycle Control ◽  
Testicular Development ◽  
Dna Ladder

Abstract To explore physiological roles of BCL-W, a prosurvival member of the BCL-2 protein family, we generated transgenic (TG) mice overexpressing Bcl-w driven by a chicken β-actin promoter. Male Bcl-w TG mice developed normally but were infertile. The adult TG testes displayed disrupted spermatogenesis with various severities ranging from thin seminiferous epithelium containing less germ cells to Sertoli cell-only appearance. No overpopulation of any type of germ cells was observed during testicular development. In contrast, the developing TG testes displayed decreased number of spermatogonia, degeneration, and detachment of spermatocytes and Sertoli cell vacuolization. The proliferative activity of germ cells was significantly reduced during testicular development and spermatogenesis, as determined by in vivo and in vitro 5′-bromo-2′deoxyuridine incorporation assays. Sertoli cells were structurally and functionally normal. The degenerating germ cells were TUNEL-negative and no typical apoptotic DNA ladder was detected. Our data suggest that regulated spatial and temporal expression of BCL-W is required for normal testicular development and spermatogenesis, and overexpression of BCL-W inhibits germ cell cycle entry and/or cell cycle progression leading to disrupted spermatogenesis.

scholarly journals Cyclin A expression is under negative transcriptional control during the cell cycle.

1996 ◽  
Vol 16 (7) ◽  
pp. 3789-3798 ◽  
Author(s):  
X Huet ◽  
J Rech ◽  
A Plet ◽  
A Vié ◽  
J M Blanchard
Keyword(s):  
Cell Cycle ◽  
Transcriptional Repression ◽  
Transcriptional Control ◽  
Cell Cycle Progression ◽  
Cyclin A ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Proliferating Cells

Transcription of the gene coding for cyclin A, a protein required for S-phase transit, is cell cycle regulated and is restricted to proliferating cells. To further explore transcriptional regulation linked to cell division cycle control, a genomic clone containing 5' flanking sequences of the murine cyclin A gene was isolated. When it was fused to a luciferase reporter gene, it was shown to function as a proliferation-regulated promoter in NIH 3T3 cells. Transcription of the mouse cyclin A gene is negatively regulated by arrest of cell proliferation. A mutation of a GC-rich sequence conserved between mice and humans is sufficient to relieve transcriptional repression, resulting in a promoter with constitutively high activity. In agreement with this result, in vivo footprinting reveals a protection of the cell cycle-responsive element in G0/early G1 cells which is not observed at later stages of the cell cycle. Moreover, the footprint is present in dimethyl sulfoxide-induced differentiating and not in proliferating Friend erythroleukemia cells. Conversely, two other sites, which in vitro bind ATF-1 and NF-Y, respectively, are constitutively occupied throughout cell cycle progression.

scholarly journals C1orf109L promote R-loop accumulation induced DNA damage to inhibit cell growth

2019 ◽  
Author(s):  
Dou Peng ◽  
Li Yiqun ◽  
Xie Wanqiu ◽  
Zhang Xiaoqing ◽  
Zhang Dandan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Death ◽  
Cell Growth ◽  
Genome Instability ◽  
Cell Death Pathway ◽  
Unknown Gene ◽  
Lower Expression

AbstractAs a function unknown gene, C1orf109 is lower expression in various cells. Here, we reported that C1orf109L, the longest variant of C1orf109, which interacted with R-loop-regulating proteins to trigger R-loop, a three-stranded nucleic acid structure frequently mediated genome instability, accumulation. C1orf109L induce chronic DNA damage to promote P21 upregulation and strongly inhibits cell growth in vitro and in vivo by arresting the cell cycle in the G2 phase. With camptothecin (CPT), an R-loop activator, treatment, C1orf109L further triggers R-loop accumulation-induced DNA damage and promotes cell death by activating cell-death pathway. Furthermore, CPT treatment increases C1orf109L ubiquitination and turnover, which inhibits cell death and promotes the G0/G1 phase of the cell cycle. Therefore, our data illustrated the mechanisms underlying C1orf109L-related cell growth inhibition and provide feasibility and limitations for C1orf109L as a potential target for cancer therapy.

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