The ZF87/MAZ transcription factor functions as a growth suppressor in fibroblasts

2000 ◽  
Vol 78 (4) ◽  
pp. 477-485 ◽  
Author(s):  
Matthew C Stubbs ◽  
InSung Min ◽  
Marc W Izzo ◽  
Ravikumar Rallapalli ◽  
Assia Derfoul ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Slow Growth ◽  
Chemotherapeutic Agent ◽  
S Phase ◽  
G1 Arrest ◽  
Zinc Finger Transcription Factor ◽  
Protein Levels ◽  
Myc Gene ◽  
Growth Suppressor

ZF87/MAZ is a zinc finger transcription factor that activates expression of tissue-specific genes and represses expression of the c-myc proto-oncogene. Infection of NIH3T3 fibroblasts with a retrovirus expressing ZF87/MAZ leads to a significant reduction in G418-resistant colonies, compared to cells infected with a retroviral control. Further, only a small fraction of the G418-resistant colonies express ZF87/MAZ. When the ZF87/MAZ-expressing colonies are expanded, they demonstrate a slow growth phenotype, a delayed transit through G1 phase and a decrease in endogenous c-myc gene expression and cyclin A and cyclin E protein levels. Consistent with a partial G1 arrest, the ZF87/MAZ-expressing cells show a reduced sensitivity to the S phase specific chemotherapeutic agent camptothecin. These data indicate that ZF87/MAZ is a growth suppressor protein in nontransformed cells, in part, by affecting the levels of key cell cycle regulatory proteins.Key words: cell cycle, ZF87/MAZ, cancer.

scholarly journals The Saccharomyces cerevisiae YAK1 gene encodes a protein kinase that is induced by arrest early in the cell cycle.

1991 ◽  
Vol 11 (8) ◽  
pp. 4045-4052 ◽  
Author(s):  
S Garrett ◽  
M M Menold ◽  
J R Broach
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Specific Activity ◽  
S Phase ◽  
Protein Kinase Activity ◽  
Dependent Protein Kinase ◽  
Protein Levels ◽  
Cycle Arrest ◽  
Dependent Protein

Null mutations in the gene YAK1, which encodes a protein with sequence homology to known protein kinases, suppress the cell cycle arrest phenotype of mutants lacking the cyclic AMP-dependent protein kinase (A kinase). That is, loss of the YAK1 protein specifically compensates for loss of the A kinase. Here, we show that the protein encoded by YAK1 has protein kinase activity. Yak1 kinase activity is low during exponential growth but is induced at least 50-fold by arrest of cells prior to the completion of S phase. Induction is not observed by arrest at stages later in the cell cycle. Depending on the arrest regimen, induction can occur either by an increase in Yak1 protein levels or by an increase in Yak1 specific activity. Finally, an increase in Yak1 protein levels causes growth arrest of cells with attenuated A kinase activity. These results suggest that Yak1 acts in a pathway parallel to that of the A kinase to negatively regulate cell proliferation.

scholarly journals Ovol2, a zinc finger transcription factor, is dispensable for spermatogenesis in mice

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Jin Zhang ◽  
Juan Dong ◽  
Weibing Qin ◽  
Congcong Cao ◽  
Yujiao Wen ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Germ Cell ◽  
Zinc Finger ◽  
Germ Cells ◽  
Cell Development ◽  
Knockout Mouse Model ◽  
Zinc Finger Transcription Factor ◽  
Germ Cell Development ◽  
Embryonic Germ Cells ◽  
Protein Levels

AbstractOvol2, a mouse homolog of Drosophila ovo, was identified as a zinc finger transcription factor predominantly expressed in testis. However, the function of Ovol2 in postnatal male germ cell development remains enigmatic. Here, we firstly examined the mRNA and protein levels of Ovol2 in developing mouse testes by RT-qPCR and western blot and found that both mRNA and protein of Ovol2 are continually expressed in postnatal developing testes from postnatal day 0 (P0) testes to adult testes (P56) and exhibits its higher level at adult testis. Further testicular immuno-staining revealed that OVOL2 is highly expressed in the spermatogonia, spermatocytes and round spermatids. Interestingly, our conditional ovol2 knockout mouse model show that loss of ovol2 in embryonic germ cells does not affect fecundity in mice. Our data also show that Ovol1 may have compensated for the loss of Ovol2 functions in germ cells. Overall, our data indicate that ovol2 is dispensable for germ cell development and spermatogenesis.

scholarly journals Antagonistic regulation of Fus2p nuclear localization by pheromone signaling and the cell cycle

2009 ◽  
Vol 184 (3) ◽  
pp. 409-422 ◽  
Author(s):  
Casey A. Ydenberg ◽  
Mark D. Rose
Keyword(s):  
Cell Cycle ◽  
S Phase ◽  
Yeast Cells ◽  
Transcriptional Level ◽  
G1 Arrest ◽  
Cycle Arrest ◽  
Pheromone Signaling ◽  
Dependent Inhibition ◽  
Induced Proteins ◽  
Mating Projection

When yeast cells sense mating pheromone, they undergo a characteristic response involving changes in transcription, cell cycle arrest in early G1, and polarization along the pheromone gradient. Cells in G2/M respond to pheromone at the transcriptional level but do not polarize or mate until G1. Fus2p, a key regulator of cell fusion, localizes to the tip of the mating projection during pheromone-induced G1 arrest. Although Fus2p was expressed in G2/M cells after pheromone induction, it accumulated in the nucleus until after cell division. As cells arrested in G1, Fus2p was exported from the nucleus and localized to the nascent tip. Phosphorylation of Fus2p by Fus3p was required for Fus2p export; cyclin/Cdc28p-dependent inhibition of Fus3p during late G1 through S phase was sufficient to block exit. However, during G2/M, when Fus3p was activated by pheromone signaling, Cdc28p activity again blocked Fus2p export. Our results indicate a novel mechanism by which pheromone-induced proteins are regulated during the transition from mitosis to conjugation.

scholarly journals The p110 Isoform of the CDP/Cux Transcription Factor Accelerates Entry into S Phase

2006 ◽  
Vol 26 (6) ◽  
pp. 2441-2455 ◽  
Author(s):  
Laurent Sansregret ◽  
Brigitte Goulet ◽  
Ryoko Harada ◽  
Brian Wilson ◽  
Lam Leduy ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Cell Cycle Progression ◽  
S Phase ◽  
Proteolytic Processing ◽  
Experimental Conditions ◽  
Division Rate ◽  
Cycle Progression ◽  
Processing Event

ABSTRACT The CDP/Cux transcription factor was previously found to acquire distinct DNA binding and transcriptional properties following a proteolytic processing event that takes place at the G1/S transition of the cell cycle. In the present study, we have investigated the role of the CDP/Cux processed isoform, p110, in cell cycle progression. Populations of cells stably expressing p110 CDP/Cux displayed a faster division rate and reached higher saturation density than control cells carrying the empty vector. p110 CDP/Cux cells reached the next S phase faster than control cells under various experimental conditions: following cell synchronization in G0 by growth factor deprivation, synchronization in S phase by double thymidine block treatment, or enrichment in G2 by centrifugal elutriation. In each case, duration of the G1 phase was shortened by 2 to 4 h. Gene inactivation confirmed the role of CDP/Cux as an accelerator of cell cycle progression, since mouse embryo fibroblasts obtained from Cutl1z/z mutant mice displayed a longer G1 phase and proliferated more slowly than their wild-type counterparts. The delay to enter S phase persisted following immortalization by the 3T3 protocol and transformation with H-RasV12. Moreover, CDP/Cux inactivation hindered both the formation of foci on a monolayer and tumor growth in mice. At the molecular level, expression of both cyclin E2 and A2 was increased in the presence of p110 CDP/Cux and decreased in its absence. Overall, these results establish that p110 CDP/Cux functions as a cell cycle regulator that accelerates entry into S phase.

Chemosensitisation by poly(ADP-ribose) polymerase-1 (PARP-1) inhitor 5-aminoisoquinoline (5-AIQ) on various melanoma cell lines

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 12019-12019 ◽  
Author(s):  
S. Radulovic ◽  
S. Bjelogrlic ◽  
Z. Todorovic ◽  
M. Prostran
Keyword(s):  
Cell Cycle ◽  
Cytotoxic Activity ◽  
Cell Lines ◽  
Melanoma Cell ◽  
Cell Cycle Progression ◽  
Single Agent ◽  
S Phase ◽  
G1 Arrest ◽  
Parp 1 ◽  
Melanoma Cell Lines

12019 Background: PARP-1 facilitates DNA strand brakes repair and PARP inhibitors were investigated as enhancers of chemoradiotherapy. We investigated whether 5-AIQ potentates the effect of doxorubicin (DOXO), cisplatin (CDDP) and paclitaxel (Ptx) on human (slow-growing) FemX and murine (fast-growing) B16 melanoma cell lines. Methods: Twenty-four hours after cells were seeded in 96 well plates, cytotoxic drugs and 5-AIQ were added to cell medium. For evaluation of single-agent activity, drugs were applied in concentration ranges as follows: CDDP (0.3–30 μM), DOXO (0.1–3 μM), Ptx (1–100 ηM), 5-AIQ (1–100 μM). 5-AIQ (3μM) was combined with CDDP (0.1, 0.3, 1 μM), DOXO (10, 3, 100 ηM), or Ptx (1, 3, 10 ηM). Incubation lasted for 72 hrs when SRB assay was utilized to determine individual and combine activity (interactions calculated with isobole method). For cell cycle analysis B16 cells were seeded on 6 well plates and treated with each drug alone and combinations, using the same concentrations as those for investigation of combine cytotoxic activity. Cell cycle was determined after 72 hrs, on FACS Calibur with propidium iodide dye. Results: 5-AIQ induced minimal changes in cell viability and cell cycle progression on both cell lines, compared to non-treated control. CDDP revealed high activity against FemX (IC50 = 2.85 μM) and B16 cells (IC50 = 8.84 μM), and G0/G1 arrest. In B16 cells 5-AIQ multiply enhanced CDDP’s activity with strong synergistic interaction and cells slightly driven to S phase. Synergism was also detected on B16 cells treated with combination of DOXO (IC50 = 0.2 μM on B16 and 0.89 μM on FemX) and 5-AIQ when DOXO was applied in low concentrations (10 and 30 ηM), while 5-AIQ did not interfere with cell cycle changes. Cytotoxicity of Ptx (IC50 = 6.16 ηM on B16 and <1 ηM on FemX) was stimulated only at higher concentrations. 5-AIQ stimulated G0/G1 and S phase arrest on B16 cells with Ptx of 3 and 10 ηM, respectively. In FemX cells, most of the interactions of 5-AIQ with CDDP, DOXO, and Ptx revealed as antagonistic. Conclusions: PARP-1 inhibitor 5-AIQ enhances cytotoxic activity of both DNA damaging and agents with different mechanism of action, but the effect varies between cell lines with different proliferation rate. No significant financial relationships to disclose.

scholarly journals Inhibitory Effects of 1α,25-Dihydroxyvitamin D3 on the G1–S Phase-Controlling Machinery

2001 ◽  
Vol 15 (8) ◽  
pp. 1370-1380 ◽  
Author(s):  
Simon Skjøde Jensen ◽  
Mogens Winkel Madsen ◽  
Jiri Lukas ◽  
Lise Binderup ◽  
Jiri Bartek
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Time Course ◽  
Cancer Cell Line ◽  
Cyclin A ◽  
S Phase ◽  
Cyclin D3 ◽  
G1 Arrest ◽  
Dihydroxyvitamin D3 ◽  
Mcf 7

Abstract The nuclear hormone 1α,25-dihydroxyvitamin D3 induces cell cycle arrest, differentiation, or apoptosis depending on target cell type and state. Although the antiproliferative effect of 1α,25-dihydroxyvitamin D3 has been known for years, the molecular basis of the cell cycle blockade by 1α,25-dihydroxyvitamin D3 remains largely unknown. Here we have investigated the mechanisms underlying the G1 arrest induced upon 1α,25-dihydroxyvitamin D3 treatment of the human breast cancer cell line MCF-7. Twenty-four-hour exposure of exponentially growing MCF-7 cells to 1α,25-dihydroxyvitamin D3 impeded proliferation by preventing S phase entry, an effect that correlated with appearance of the growth-suppressing, hypophosphorylated form of the retinoblastoma protein (pRb), and modulation of cyclin-dependent kinase (cdk) activities of cdk-4, -6, and -2. Time course immunochemical and biochemical analyses of the cellular and molecular effects of 1α,25-dihydroxyvitamin D3 treatment for up to 6 d revealed a dynamic chain of events, preventing activation of cyclin D1/cdk4, and loss of cyclin D3, which collectively lead to repression of the E2F transcription factors and thus negatively affected cyclin A protein expression. While the observed 10-fold inhibition of cyclin D1/cdk 4-associated kinase activity appeared independent of cdk inhibitors, the activity of cdk 2 decreased about 20-fold, reflecting joint effects of the lower abundance of its cyclin partners and a significant increase of the cdk inhibitor p21CIP1/WAF1, which blocked the remaining cyclin A(E)/cdk 2 complexes. Together with a rapid down-modulation of the c-Myc oncoprotein in response to 1α,25-dihydroxyvitamin D3, these results demonstrate that 1α,25-dihydroxyvitamin D3 inhibits cell proliferation by targeting several key regulators governing the G1/S transition.

Constitutive expression of the E2F1 transcription factor in fibroblasts alters G0 and S phase transit following serum stimulation

1996 ◽  
Vol 74 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Thomas J. Logan ◽  
Kelly L. Jordan ◽  
David J. Hall
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Cell Lines ◽  
Constitutive Expression ◽  
S Phase ◽  
G1 Phase ◽  
Serum Starvation ◽  
Serum Stimulation ◽  
G0 Phase ◽  
E2f1 Transcription Factor

The E2F1 transcription factor was constitutively expressed in NIH3T3 fibroblasts to determine its effect on the cell cycle. These E2F1 cell lines were not tightly synchronized in G0 phase of the cell cycle following serum starvation, as are normal fibroblasts. Instead, the cells are spread throughout G0 and G1 phase with a portion of the population initiating DNA synthesis. Upon serum stimulation, the remaining cells in G0/G1 begin to enter S phase immediately but with a reduced rate. Constitutive expression of E2F1 appears to primarily affect the G0 phase, since transit of proliferating E2F1 cell lines through G1 phase is the same as control cells. Consistent with a shortened G0 phase, the E2F1 cell lines have a significantly reduced cellular volume. Additionally, the first S phase after serum stimulation, but not subsequent S phases, is nearly doubled in the E2F1 cell lines compared with control cells. Cell lines expressing a deletion mutant of E2F1 (termed E2F1d87), known to significantly affect cell shape, have cell cycle and volume characteristics similar to the E2F1 expressing cells. However, all S phase durations are considerably lengthened and the cells demonstrate delayed growth after plating.Key words: cell cycle, E2F1 transcription factor, G0/G1 phase.

scholarly journals Expression of dominant-negative mutant DP-1 blocks cell cycle progression in G1.

1996 ◽  
Vol 16 (7) ◽  
pp. 3698-3706 ◽  
Author(s):  
C L Wu ◽  
M Classon ◽  
N Dyson ◽  
E Harlow
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Cell Cycle Progression ◽  
S Phase ◽  
Dominant Negative ◽  
Functional Domains ◽  
Dominant Negative Mutant ◽  
G1 Arrest ◽  
Wild Type ◽  
Cycle Progression

Unregulated expression of the transcription factor E2F promotes the G1-to-S phase transition in cultured mammalian cells. However, there has been no direct evidence for an E2F requirement in this process. To demonstrate that E2F is obligatory for cell cycle progression, we attempted to inactivate E2F by overexpressing dominant-negative forms of one of its heterodimeric partners, DP-1. We dissected the functional domains of DP-1 and separated the region that facilitate heterodimer DNA binding from the E2F dimerization domain. Various DP-1 mutants were introduced into cells via transfection, and the cell cycle profile of the transfected cells was analyzed by flow cytometry. Expression of wild-type DP-1 or DP-1 mutants that bind to both DNA and E2F drove cells into S phase. In contrast, DP-1 mutants that retained E2F binding but lost DNA binding arrested cells in the G1 phase of the cell cycle. The DP-1 mutants that were unable to bind DNA resulted in transcriptionally inactive E2F complexes, suggesting that the G1 arrest is caused by formation of defective E2F heterodimers. Furthermore, the G1 arrest instigated by these DP-1 mutants could be rescued by coexpression of wild-type E2F or DP protein. These experiments define functional domains of DP and demonstrate a requirement for active E2F complexes in cell cycle progression.

scholarly journals Stat Proteins Control Lymphocyte Proliferation by Regulating p27Kip1 Expression

1998 ◽  
Vol 18 (4) ◽  
pp. 1996-2003 ◽  
Author(s):  
Mark H. Kaplan ◽  
Carla Daniel ◽  
Ulrike Schindler ◽  
Michael J. Grusby
Keyword(s):  
Cell Cycle ◽  
Proliferative Response ◽  
S Phase ◽  
Interleukin 4 ◽  
Activated T Cells ◽  
Stat Proteins ◽  
Protein Levels ◽  
Proliferation Of Lymphocytes ◽  
Cytokine Stimulation ◽  
Stimulation Of

ABSTRACT The proliferation of lymphocytes in response to cytokine stimulation is essential for a variety of immune responses. Recent studies with signal transducer and activator of transcription 6 (Stat6)-deficient mice have demonstrated that this protein is required for the normal proliferation of lymphocytes in response to interleukin-4 (IL-4). In this report, we show that the impaired IL-4-induced proliferative response of Stat6-deficient lymphocytes is not due to an inability to activate alternate signaling pathways, such as those involving insulin receptor substrates, or to a failure to upregulate IL-4 receptor levels. Cell cycle analysis showed that the percentage of Stat6-deficient lymphocytes that transit from the G1 to the S phase of the cell cycle following IL-4 stimulation is lower than that of control lymphocytes. Although the regulation of many genes involved in the control of cytokine-induced proliferation is normal in Stat6-deficient lymphocytes, protein levels of the cdk inhibitor p27Kip1 were found to be markedly dysregulated. p27Kip1 is expressed at significantly higher levels in Stat6-deficient lymphocytes than in control cells following IL-4 stimulation. The higher level of p27Kip1 expression seen in IL-4-stimulated Stat6-deficient lymphocytes correlates with decreased cdk2-associated kinase activity and is the result of the increased accumulation of protein rather than altered mRNA expression. Similarly, higher levels of p27Kip1 protein expression are also seen following IL-12 stimulation of Stat4-deficient lymphocytes than are seen following stimulation of control cells. These data suggest that Stat proteins may control the cytokine-induced proliferative response of activated T cells by regulating the expression of cell cycle inhibitors so that cyclin-cdk complexes may function to promote transition from the G1 to the S phase of the cell cycle.

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