scholarly journals Characterization of the S-phase-specific transcription regulatory elements in a DNA replication-independent testis-specific H2B (TH2B) histone gene.

1990 ◽  
Vol 10 (2) ◽  
pp. 585-592 ◽  
Author(s):  
I W Hwang ◽  
K Lim ◽  
C B Chae
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Biological Significance ◽  
Regulatory Elements ◽  
S Phase ◽  
Phase Cell ◽  
Dependent Manner ◽  
Base Pairs ◽  
Pachytene Spermatocytes ◽  
Cloned Gene

The testis-specific H2B histone (TH2B) gene is expressed in pachytene spermatocytes of meiotic prophase I during rat spermatogenesis. The TH2B RNA and histones are not synthesized in any other tissues, and the synthesis is independent of DNA replication. However, the cloned TH2B gene has two DNA sequence elements which stimulate transcription of the cloned gene in an S-phase-dependent manner when introduced into somatic cells. The factors interacting with the two elements, CCAAT at -127 base pairs and octamer ATTTGCAT at -93 base pairs, interact with each other to bring about a maximum stimulation of S-phase-dependent transcription. The level of CCAAT and octamer-binding proteins is unchanged during the cell cycle, and the S-phase-dependent transcription of TH2B and endogenous mouse H2B genes does not require synthesis of new proteins during the S phase. Cell cycle-specific posttranslational modification of regulatory proteins may be responsible for the S-phase-dependent transcription of H2B histone genes. The biological significance of the presence of S-phase-specific transcription regulatory elements in the DNA replication-independent and tissue-specific TH2B gene is not known.

scholarly journals Characterization of the S-phase-specific transcription regulatory elements in a DNA replication-independent testis-specific H2B (TH2B) histone gene

1990 ◽  
Vol 10 (2) ◽  
pp. 585-592
Author(s):  
I W Hwang ◽  
K Lim ◽  
C B Chae
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Biological Significance ◽  
Regulatory Elements ◽  
S Phase ◽  
Phase Cell ◽  
Dependent Manner ◽  
Base Pairs ◽  
Pachytene Spermatocytes ◽  
Cloned Gene

The testis-specific H2B histone (TH2B) gene is expressed in pachytene spermatocytes of meiotic prophase I during rat spermatogenesis. The TH2B RNA and histones are not synthesized in any other tissues, and the synthesis is independent of DNA replication. However, the cloned TH2B gene has two DNA sequence elements which stimulate transcription of the cloned gene in an S-phase-dependent manner when introduced into somatic cells. The factors interacting with the two elements, CCAAT at -127 base pairs and octamer ATTTGCAT at -93 base pairs, interact with each other to bring about a maximum stimulation of S-phase-dependent transcription. The level of CCAAT and octamer-binding proteins is unchanged during the cell cycle, and the S-phase-dependent transcription of TH2B and endogenous mouse H2B genes does not require synthesis of new proteins during the S phase. Cell cycle-specific posttranslational modification of regulatory proteins may be responsible for the S-phase-dependent transcription of H2B histone genes. The biological significance of the presence of S-phase-specific transcription regulatory elements in the DNA replication-independent and tissue-specific TH2B gene is not known.

scholarly journals Xanthohumol Induces Growth Inhibition and Apoptosis in Ca Ski Human Cervical Cancer Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Wai Kuan Yong ◽  
Sri Nurestri Abd Malek
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Morphological Changes ◽  
S Phase ◽  
Phase Cell ◽  
Cervical Cancer Cell Line ◽  
Dependent Manner ◽  
Cervical Cancer Cells

We investigate induction of apoptosis by xanthohumol on Ca Ski cervical cancer cell line. Xanthohumol is a prenylated chalcone naturally found in hop plants, previously reported to be an effective anticancer agent in various cancer cell lines. The present study showed that xanthohumol was effective to inhibit proliferation of Ca Ski cells based on IC50values using sulforhodamine B (SRB) assay. Furthermore, cellular and nuclear morphological changes were observed in the cells using phase contrast microscopy and Hoechst/PI fluorescent staining. In addition, 48-hour long treatment with xanthohumol triggered externalization of phosphatidylserine, changes in mitochondrial membrane potential, and DNA fragmentation in the cells. Additionally, xanthohumol mediated S phase arrest in cell cycle analysis and increased activities of caspase-3, caspase-8, and caspase-9. On the other hand, Western blot analysis showed that the expression levels of cleaved PARP, p53, and AIF increased, while Bcl-2 and XIAP decreased in a dose-dependent manner. Taken together, these findings indicate that xanthohumol-induced cell death might involve intrinsic and extrinsic apoptotic pathways, as well as downregulation of XIAP, upregulation of p53 proteins, and S phase cell cycle arrest in Ca Ski cervical cancer cells. This work suggests that xanthohumol is a potent chemotherapeutic candidate for cervical cancer.

scholarly journals HiNF-P Directly Links the Cyclin E/CDK2/p220NPAT Pathway to Histone H4 Gene Regulation at the G1/S Phase Cell Cycle Transition

2005 ◽  
Vol 25 (14) ◽  
pp. 6140-6153 ◽  
Author(s):  
Angela Miele ◽  
Corey D. Braastad ◽  
William F. Holmes ◽  
Partha Mitra ◽  
Ricardo Medina ◽  
...  
Keyword(s):  
Gene Expression ◽  
Phase Transition ◽  
Cell Cycle ◽  
Cyclin E ◽  
S Phase ◽  
Phase Cell ◽  
Genome Replication ◽  
Dependent Manner ◽  
Histone H4 ◽  
Histone H4 Gene

ABSTRACT Genome replication in eukaryotic cells necessitates the stringent coupling of histone biosynthesis with the onset of DNA replication at the G1/S phase transition. A fundamental question is the mechanism that links the restriction (R) point late in G1 with histone gene expression at the onset of S phase. Here we demonstrate that HiNF-P, a transcriptional regulator of replication-dependent histone H4 genes, interacts directly with p220NPAT, a substrate of cyclin E/CDK2, to coactivate histone genes during S phase. HiNF-P and p220 are targeted to, and colocalize at, subnuclear foci (Cajal bodies) in a cell cycle-dependent manner. Genetic or biochemical disruption of the HiNF-P/p220 interaction compromises histone H4 gene activation at the G1/S phase transition and impedes cell cycle progression. Our results show that HiNF-P and p220 form a critical regulatory module that directly links histone H4 gene expression at the G1/S phase transition to the cyclin E/CDK2 signaling pathway at the R point.

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 ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
S Phase ◽  
Expression Level ◽  
Specific Gene ◽  
Dependent Manner ◽  
Replication Checkpoint ◽  
Checkpoint Kinases ◽  
Phase Arrest ◽  
S Phase Arrest

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.

scholarly journals Inhibition of DNA Replication and Induction of S Phase Cell Cycle Arrest by G-rich Oligonucleotides

2001 ◽  
Vol 276 (46) ◽  
pp. 43221-43230 ◽  
Author(s):  
Xiaohua Xu ◽  
Fofi Hamhouyia ◽  
Shelia D. Thomas ◽  
Tom J. Burke ◽  
Allicia C. Girvan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Cell Cycle Arrest ◽  
S Phase ◽  
Phase Cell ◽  
Cycle Arrest

scholarly journals S-phase-specific transcription regulatory elements are present in a replication-independent testis-specific H2B histone gene.

1989 ◽  
Vol 9 (3) ◽  
pp. 1005-1013 ◽  
Author(s):  
I Hwang ◽  
C B Chae
Keyword(s):  
Dna Synthesis ◽  
Regulatory Element ◽  
Regulatory Elements ◽  
S Phase ◽  
Upstream Region ◽  
Base Pairs ◽  
Regulated Expression ◽  
Dna Fragment ◽  
Pachytene Spermatocytes

The testis-specific H2B histone (TH2B) gene is expressed in pachytene spermatocytes during meiotic prophase I in the absence of any significant DNA synthesis. Unlike somatic histones, synthesis of testis-specific histones is not affected by inhibitors of DNA synthesis. A genomic rat TH2B gene was cloned by using a DNA fragment derived from TH2B cDNA as a probe. Expression of the cloned TH2B was investigated by gene transfer experiments. From these studies, we found that the 5' upstream region of the cloned TH2B gene contained S-phase-specific transcription elements which regulated expression of a reporter gene in an S-phase-specific manner. The S-phase-regulatory element was found to be located in two regions containing CCAAT elements between -153 and -110 base pairs (bp) and an octamer element (ATTTGCAT) between -109 and -84 bp. The two regions were required for a maximal stimulation of transcription of the cloned TH2B gene in S phase. On the other hand, only the octamer element was reported be important for the S-phase-specific transcription of human H2B gene. Since the synthesis of the TH2B histone is independent of DNA synthesis and specific for pachytene spermatocytes in vivo, the presence of the S-phase-specific transcription regulatory elements in the TH2B gene is surprising.

scholarly journals Sulforaphane induces S-phase arrest and apoptosis via p53-dependent manner in gastric cancer cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuan Wang ◽  
Huazhang Wu ◽  
Nannan Dong ◽  
Xu Su ◽  
Mingxiu Duan ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Western Blot ◽  
Cell Apoptosis ◽  
S Phase ◽  
Phase Cell ◽  
Dependent Manner ◽  
Gastric Cancer Cells ◽  
Dose Dependent

AbstractSulforaphane (SFN) extracted from broccoli sprout has previously been investigated for its potential properties in cancers, however, the underlying mechanisms of the anticancer activity of SFN remain not fully understood. In the present study, we investigate the effects of SFN on cell proliferation, cell cycle, cell apoptosis, and also the expression of several cell cycle and apoptosis-related genes by MTT assay, flow cytometry and western blot analysis in gastric cancer (GC) cells. The results showed that SFN could impair the colony-forming ability in BGC-823 and MGC-803 cell lines compared with the control. In addition, SFN significantly suppressed cell proliferation by arresting the cell cycle at the S phase and enhancing cell apoptosis in GC cells in a dose-dependent manner. Western blot results showed that SFN treatment significantly increased the expression levels of p53, p21 and decreased CDK2 expression, which directly regulated the S phase transition. The Bax and cleaved-caspase-3 genes involved in apoptosis executive functions were significantly increased in a dose-dependent manner in BGC-823 and MGC-803 cells. These results suggested that SFN-induced S phase cell cycle arrest and apoptosis through p53-dependent manner in GC cells, which suggested that SFN has a potential therapeutic application in the treatment and prevention of GC.

Norcantharidin Inhibits Pre-Replicative Complexes Assembly of HepG2 Cells

2013 ◽  
Vol 41 (03) ◽  
pp. 665-682 ◽  
Author(s):  
Sansan Chen ◽  
Xinming Qu ◽  
Pei Wan ◽  
Qing Wen Li ◽  
Ziyi Wang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Hepg2 Cells ◽  
Nuclear Translocation ◽  
Anticancer Therapy ◽  
Inhibitory Effect ◽  
S Phase ◽  
G1 Phase ◽  
Dependent Manner ◽  
Dose Dependent

Norcantharidin (NCTD) is currently used for anticancer therapy but the exact mechanism of action remains unknown. Pre-replicative complexes (pre-RCs) are essential for cell DNA replication and highly related to malignant proliferation. Here, we examined the inhibitory effect of NCTD on pre-RC components in HepG2 cells. We showed that NCTD induced degradation of Cdc6 and Mcm2 in a dose-dependent manner. Under 100 μM NCTD concentration, about 70% of Cdc6 and 50% of Mcm2 were degraded. In addition, the nuclear translocation of Mcm6 was inhibited by NCTD. Further studies aiming at G1 synchronous cells showed that, NCTD reduced the chromatin-bound Cdc6, Mcm2 and Mcm6. Moreover, the cells were blocked from entering the S phase and accumulated at the G1 phase when released synchronously into the cell cycle. Consistently, the DNA replication was inhibited by NCTD. Finally, the combination NCTD with Cdc6 depletion lead to more severe cytotoxicity (88%) than NCTD (52%) and Cdc6 depletion (39%) alone. A synergic cytotoxicity was observed between Cdc6 depletion and NCTD. In conclusion, our results demonstrate that NCTD inhibits pre-RC assembly; subsequently blocks the G1 to S transition; and inhibits DNA replication in HepG2 cells. Pre-RCs are an intriguing target for cancer therapy, which merits further investigations for anticancer development.

scholarly journals Topoisomerase IIα Prevents, But Does Not Resolve, Ultrafine Anaphase Bridges By Two Mechanisms

2019 ◽  
Author(s):  
Simon Gemble ◽  
Géraldine Buhagiar-Labarchède ◽  
Rosine Onclercq-Delic ◽  
Sarah Lambert ◽  
Mounira Amor-Guéret
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
S Phase ◽  
Cycle Phase ◽  
Dependent Manner ◽  
Topoisomerase Iiα ◽  
Anaphase Bridges ◽  
Double Stranded Dna ◽  
A Cell ◽  
Cycle Dependent

AbstractTopoisomerase IIα (Topo IIα), a well-conserved double-stranded DNA (dsDNA)-specific decatenase, processes dsDNA catenanes resulting from DNA replication during mitosis. Topo IIα defects lead to an accumulation of ultrafine anaphase bridges (UFBs), a type of chromosome non-disjunction. Topo IIα has been reported to resolve DNA anaphase threads, possibly accounting for the increase in UFB frequency upon Topo IIα inhibition. We hypothesized that the excess UFBs might also result, at least in part, from an impairment of the prevention of UFB formation by Topo IIα. We found that Topo IIα inhibition promotes UFB formation without affecting UFB resolution during anaphase. Moreover, we showed that Topo IIα inhibition promotes the formation of two types of UFBs depending on cell-cycle phase. Topo IIα inhibition during S-phase compromises complete DNA replication, leading to the formation of UFB-containing unreplicated DNA, whereas Topo IIα inhibition during mitosis impedes DNA decatenation at metaphase-anaphase transition, leading to the formation of UFB-containing DNA catenanes. Thus, Topo IIα activity is essential to prevent UFB formation in a cell-cycle dependent manner, but dispensable for UFB resolution during anaphase.

Sign in / Sign up

Export Citation Format

Share Document