&lt;b&gt;INHIBITION OF DNA SYNTHESIS BY EDTA AND ITS CANCELLATION BY ZINC IN PRIMARY CULTURES OF ADULT RAT &lt;/b&gt;&lt;b&gt;HEPATOCYTES &lt;/b&gt;

Watanabe, Kazuto; Hasegawa, Kaoru; Ohtake, Hideki; Tohyama, Chiharu; Koga, Mutuyosi

doi:10.2220/biomedres.14.99

Cited by 14 publications

(16 citation statements)

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“…This finding indicates that zinc is needed at the G1/S transition of the cell cycle for DNA synthesis. A similar phenomenon was observed when ethylenediaminetetraacetic acid (EDTA) was added to primary cultures of adult rat hepatocytes [6]. Zinc is also required for a process contemporaneous with the S phase and for subsequent transition of the cells through G2/M [7].…”

Section: Introductionsupporting

confidence: 52%

Transient fluctuations of intracellular zinc ions in cell proliferation

Maret

2009

Experimental Cell Research

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Section: Introductionsupporting

confidence: 52%

Transient fluctuations of intracellular zinc ions in cell proliferation

Maret

2009

Experimental Cell Research

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“…Yet, contradictory findings regarding the relationship between the appearance of MT in hepatocyte culture and DNA synthesis have also been reported. 16 Although some studies have demonstrated MT induction by different growth factors in cell MT gene expression as influenced by growth factors has not been studied extensively in rat hepatocytes. The current work was therefore undertaken to investigate MT expression in hepatocytes under growth stimuli.…”

mentioning

confidence: 99%

Induction of metallothionein gene expression by epidermal growth factor and its inhibition by transforming growth factor-β and dexamethasone in rat hepatocytes

Moffatt

Plaa

Denizeau³

1995

Hepatology

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Metallothionein (MT) is a small cysteine-rich protein thought to be mainly involved in metal regulation and detoxification. The implication of MT in cell growth and differentiation has also been suggested. This latter hypothesis was further investigated in adult rat hepatocytes induced to proliferate by epidermal growth factor (EGF). Exposure of hepatocytes to EGF resulted in significant increases (approximately twofold) in MT protein and MT-1 messenger RNA (mRNA) levels, which were maximal after 48 hours. As revealed by nuclear run-on analysis, these changes were the result of transcriptional activation. Increases of MT occurred concomitantly with stimulation of DNA synthesis (48 hours). Addition of ZnSO4 or dexamethasone (Dex) was also effective at inducing MT protein (approximately 3.6 to 3.3 times) and mRNA. Combined addition of Zn and EGF produced an additive increase in MT protein and MT-1 mRNA levels. When both Dex and EGF were present together, the EGF-induced MT protein and mRNA expression was lost, whereas it had only minor inhibitory effects on DNA synthesis. Transforming growth factor beta (TGF-beta), a known antagonist of EGF on hepatocytes, blocked the EGF-induced MT accumulation and stimulation of DNA synthesis. In addition, under the same conditions, the EGF-induced c-fos mRNA accumulation was blocked by Dex whereas TGF-beta had no effect. These results show that growth factors believed to play a role in liver regeneration can also modulate MT gene expression in vitro. This modulation does not strictly parallel that of DNA synthesis. The possibility that c-fos stimulation may play a role in MT induction by EGF cannot be ruled out.

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“…Thus, the ratio of cytosolic/nuclear fluorescence 7 can be used as a readout for CDK2 activity and serves a 'molecular timer' for progression 8 through the cell cycle. As described previously, CDK2 activity defines subpopulations of cells 9 with different cell fates in a population of naturally cycling cells (16,17,19,42,43). When the 10 CDK2 ratio remains low after mitosis (CDK2 low ), a cell is classified as quiescent whereas when 11 CDK2 activity increases above a defined threshold within 4 hrs after mitosis (CDK2 inc ), a cell is 12 born committed to cell cycle entry ( Figure 2A).…”

Section: Mild Zn 2+ Deficiency Induces Cellular Quiescence and Stallimentioning

confidence: 76%

“…Analysis of mitosis events revealed that these cells did not 7 divide before entering the CDK2 low state. These results suggest a significant increase in the 8 number of cells that go quiescent after mitosis and the emergence of a new cell fate, where cells 9 attempt to re-enter the cell cycle but stall part-way through under conditions of Zn 2+ deficiency. 10 To further define how Zn 2+ deficiency influences cell fate and characterize the 11 consequences of the altered CDK2 activity profile in ZD cells, we examined a downstream 12 CDK2 substrate, retinoblastoma protein (Rb).…”

Section: Mild Zn 2+ Deficiency Induces Cellular Quiescence and Stallimentioning

confidence: 87%

“…7 To assess how the three nutritional Zn 2+ regimes influenced cellular proliferation, we 8 counted cells as a function of time. Naturally cycling cells expressing H2B-mCherry were 9 imaged for 60 hrs and cells in each frame were segmented and counted using a custom 10 automated analysis as described in the Supplementary Note. ZD growth conditions exhibited 11 significantly reduced cell counts over time compared to MM and ZR conditions, with cell 12 proliferation effectively halted after about 15 hrs ( Figure 1B).…”

Section: Introductionmentioning

confidence: 99%

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Single Cell Analysis Reveals Multiple Requirements for Zinc in the Mammalian Cell Cycle

Guerinot

Damon

Tay

et al. 2019

Preprint

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8Despite recognition of the fundamental role of zinc (Zn 2+ ) for growth and proliferation, 9 mechanisms of how Zn 2+ deficiency arrests these processes remain enigmatic. We induced 10 subtle intracellular Zn 2+ perturbations and tracked asynchronously cycling cells throughout 11 division using fluorescent reporters, high throughput microscopy, and quantitative analysis. We 12 found that Zn 2+ deficiency induces quiescence and Zn 2+ resupply stimulates cell-cycle reentry. 13 By monitoring single cells after Zn 2+ deprivation, we found that depending on where cells were 14 in the cell cycle, they either went quiescent or entered the cell cycle but stalled in S phase. 15 Stalled cells were defective in DNA synthesis and had increased DNA damage levels, suggesting 16 a role for Zn 2+ in maintaining genome integrity. Finally, we found that Zn 2+ deficiency-induced 17 quiescence does not require the cell-cycle inhibitor p21. Overall, our study provides new 18 insights into when Zn 2+ is required during the mammalian cell cycle and the consequences Zn 2+ 19 deficiency. 20 21 of Zn 2+ deficiency are diverse and can be organism specific, one defining feature is universal: 1 Zn 2+ deficient cells fail to divide and proliferate normally, leading to organismal growth 2 impairment (5). Despite recognition of the fundamental role of Zn 2+ for proliferation, the 3 mechanisms of how Zn 2+ deficiency leads to cell-cycle arrest at the cellular and molecular level 4 remain poorly defined. 5Eukaryotic cell proliferation is governed by the cell-division cycle, a series of highly 6 choreographed steps that involve gap (G1), DNA replication (S-phase), gap (G2), and mitosis 7 (M) phases. Regulated transitions between proliferative and quiescent (i.e. reversible non-8 proliferative) states are essential for maintaining genome integrity and tissue homeostasis, 9 ensuring proper development, and preventing tumorigenesis. Given the essentiality of Zn 2+ for 10 growth and proliferation, a fundamental question is whether Zn 2+ serves as a nutrient, like amino 11 acids, whether it affects the rate of cell cycle progression, or whether it is required at a specific 12 phase of the cell cycle. Pioneering work by Chesters et al sought to define precisely when Zn 2+ 13is required in the mammalian cell cycle. By chelating Zn 2+ at different timepoints after release 14 from serum starvation-induced quiescence, they found that Zn 2+ was important for thymidine 15 incorporation and thus DNA synthesis, leading to the conclusion that Zn 2+ was required for the 16 G1 to S transition (6). Subsequent studies confirmed that treatment of mammalian cells with 17 high concentrations of metal chelators (DTPA and EDTA) seemed to compromise DNA 18 synthesis (7-10). However, later studies by Chesters et al suggested that after cells passed the 19 restriction point in mid-G1 there was no further Zn 2+ requirement for DNA synthesis in S phase, 20 but rather Zn 2+ was needed to transition from G2/M back into G1 (11). The restriction point is 21 classically defined as...

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<b>INHIBITION OF DNA SYNTHESIS BY EDTA AND ITS CANCELLATION BY ZINC IN PRIMARY CULTURES OF ADULT RAT </b><b>HEPATOCYTES </b>

Cited by 14 publications

References 0 publications

Transient fluctuations of intracellular zinc ions in cell proliferation

Transient fluctuations of intracellular zinc ions in cell proliferation

Induction of metallothionein gene expression by epidermal growth factor and its inhibition by transforming growth factor-β and dexamethasone in rat hepatocytes

Single Cell Analysis Reveals Multiple Requirements for Zinc in the Mammalian Cell Cycle

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