scholarly journals Changes in the stability of a human H3 histone mRNA during the HeLa cell cycle.

1991 ◽  
Vol 11 (1) ◽  
pp. 544-553 ◽  
Author(s):  
T D Morris ◽  
L A Weber ◽  
E Hickey ◽  
G S Stein ◽  
J L Stein
Keyword(s):  
Cell Cycle ◽  
Hela Cell ◽  
Half Life ◽  
Fusion Gene ◽  
S Phase ◽  
Histone Mrna ◽  
Histone Protein ◽  
Heat Induction ◽  
Hela Cell Lines ◽  
The Stability

A major component of the regulation of histone protein synthesis during the cell cycle is the modulation of the half-life of histone mRNA. We have uncoupled transcriptional and posttranscriptional regulation by using a Drosophila hsp70-human H3 histone fusion gene that produces a marked human H3 histone mRNA upon heat induction. Transcription of this gene can be switched on and off by raising and lowering cell culture temperatures, respectively. HeLa cell lines containing stably integrated copies of the fusion gene were synchronized by double thymidine block. Distinct populations of H3 histone mRNA were produced by heat induction in early S-phase, late S-phase, or G2-phase cells, and the stability of the induced H3 histone mRNA was measured. The H3 histone mRNA induced during early S phase decayed with a half-life of 110 min, whereas the same transcript induced during late S phase had a half-life of 10 to 15 min. The H3 histone mRNA induced in non-S-phase cells is more stable than that induced in late S phase, with a half-life of 40 min. Thus, the stability of histone mRNA is actively regulated throughout the cell cycle. Our results are consistent with an autoregulatory model in which the stability of histone mRNA is determined by the level of free histone protein in the cytoplasm.

scholarly journals Changes in the stability of a human H3 histone mRNA during the HeLa cell cycle

1991 ◽  
Vol 11 (1) ◽  
pp. 544-553
Author(s):  
T D Morris ◽  
L A Weber ◽  
E Hickey ◽  
G S Stein ◽  
J L Stein
Keyword(s):  
Cell Cycle ◽  
Hela Cell ◽  
Half Life ◽  
Fusion Gene ◽  
S Phase ◽  
Histone Mrna ◽  
Histone Protein ◽  
Heat Induction ◽  
Hela Cell Lines ◽  
The Stability

A major component of the regulation of histone protein synthesis during the cell cycle is the modulation of the half-life of histone mRNA. We have uncoupled transcriptional and posttranscriptional regulation by using a Drosophila hsp70-human H3 histone fusion gene that produces a marked human H3 histone mRNA upon heat induction. Transcription of this gene can be switched on and off by raising and lowering cell culture temperatures, respectively. HeLa cell lines containing stably integrated copies of the fusion gene were synchronized by double thymidine block. Distinct populations of H3 histone mRNA were produced by heat induction in early S-phase, late S-phase, or G2-phase cells, and the stability of the induced H3 histone mRNA was measured. The H3 histone mRNA induced during early S phase decayed with a half-life of 110 min, whereas the same transcript induced during late S phase had a half-life of 10 to 15 min. The H3 histone mRNA induced in non-S-phase cells is more stable than that induced in late S phase, with a half-life of 40 min. Thus, the stability of histone mRNA is actively regulated throughout the cell cycle. Our results are consistent with an autoregulatory model in which the stability of histone mRNA is determined by the level of free histone protein in the cytoplasm.

scholarly journals Regulation of histone mRNA in the unperturbed cell cycle: evidence suggesting control at two posttranscriptional steps.

1991 ◽  
Vol 11 (5) ◽  
pp. 2416-2424 ◽  
Author(s):  
M E Harris ◽  
R Böhni ◽  
M H Schneiderman ◽  
L Ramamurthy ◽  
D Schümperli ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Half Life ◽  
S Phase ◽  
Protein Synthesis Inhibitor ◽  
Mrna Levels ◽  
Histone Mrna ◽  
Synthesis Inhibitor ◽  
Processing Efficiency ◽  
Histone 3 ◽  
Cycle Regulation

The levels of histone mRNA increase 35-fold as selectively detached mitotic CHO cells progress from mitosis through G1 and into S phase. Using an exogenous gene with a histone 3' end which is not sensitive to transcriptional or half-life regulation, we show that 3' processing is regulated as cells progress from G1 to S phase. The half-life of histone mRNA is similar in G1- and S-phase cells, as measured after inhibition of transcription by actinomycin D (dactinomycin) or indirectly after stabilization by the protein synthesis inhibitor cycloheximide. Taken together, these results suggest that the change in histone mRNA levels between G1- and S-phase cells must be due to an increase in the rate of biosynthesis, a combination of changes in transcription rate and processing efficiency. In G2 phase, there is a rapid 35-fold decrease in the histone mRNA concentration which our results suggest is due primarily to an altered stability of histone mRNA. These results are consistent with a model for cell cycle regulation of histone mRNA levels in which the effects on both RNA 3' processing and transcription, rather than alterations in mRNA stability, are the major mechanisms by which low histone mRNA levels are maintained during G1.

scholarly journals Regulation of human histone gene expression: kinetics of accumulation and changes in the rate of synthesis and in the half-lives of individual histone mRNAs during the HeLa cell cycle.

1983 ◽  
Vol 3 (4) ◽  
pp. 539-550 ◽  
Author(s):  
N Heintz ◽  
H L Sive ◽  
R G Roeder
Keyword(s):  
Cell Cycle ◽  
Hela Cell ◽  
Dna Synthesis ◽  
Fold Increase ◽  
S Phase ◽  
Histone Mrna ◽  
Mrna Accumulation ◽  
Histone Mrnas ◽  
The Individual ◽  
Kinetics Of

We have analyzed the kinetics of accumulation of each of the individual core histone mRNAs throughout the HeLa cell cycle in cells synchronized by sequential thymidine and aphidicolin treatments. These analyses showed that during the S phase there was a 15-fold increase in the levels of histone mRNAs and that this resulted from both an increased rate of synthesis and a lengthening of the half-life of histone mRNAs. A comparison of the kinetics of accumulation of histone mRNA in the total cellular and nuclear RNA populations suggested an increased transcription rate through the S phase. Within 30 min after the inhibition of DNA synthesis in mid-S phase, the steady-state concentration and the rate of synthesis of histone mRNA each declined to their non-S-phase levels. Reactivation of histone mRNA accumulation could occur even after an extended mid-S-phase block in DNA synthesis. These results suggest that the mechanisms responsible for histone mRNA synthesis are not restricted to the G1/S boundary of the HeLa cell cycle, but can operate whenever DNA synthesis is occurring.

Regulation of histone mRNA in the unperturbed cell cycle: evidence suggesting control at two posttranscriptional steps

1991 ◽  
Vol 11 (5) ◽  
pp. 2416-2424
Author(s):  
M E Harris ◽  
R Böhni ◽  
M H Schneiderman ◽  
L Ramamurthy ◽  
D Schümperli ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Half Life ◽  
S Phase ◽  
Protein Synthesis Inhibitor ◽  
Mrna Levels ◽  
Histone Mrna ◽  
Synthesis Inhibitor ◽  
Processing Efficiency ◽  
Histone 3 ◽  
Cycle Regulation

The levels of histone mRNA increase 35-fold as selectively detached mitotic CHO cells progress from mitosis through G1 and into S phase. Using an exogenous gene with a histone 3' end which is not sensitive to transcriptional or half-life regulation, we show that 3' processing is regulated as cells progress from G1 to S phase. The half-life of histone mRNA is similar in G1- and S-phase cells, as measured after inhibition of transcription by actinomycin D (dactinomycin) or indirectly after stabilization by the protein synthesis inhibitor cycloheximide. Taken together, these results suggest that the change in histone mRNA levels between G1- and S-phase cells must be due to an increase in the rate of biosynthesis, a combination of changes in transcription rate and processing efficiency. In G2 phase, there is a rapid 35-fold decrease in the histone mRNA concentration which our results suggest is due primarily to an altered stability of histone mRNA. These results are consistent with a model for cell cycle regulation of histone mRNA levels in which the effects on both RNA 3' processing and transcription, rather than alterations in mRNA stability, are the major mechanisms by which low histone mRNA levels are maintained during G1.

Regulation of human histone gene expression: kinetics of accumulation and changes in the rate of synthesis and in the half-lives of individual histone mRNAs during the HeLa cell cycle

1983 ◽  
Vol 3 (4) ◽  
pp. 539-550
Author(s):  
N Heintz ◽  
H L Sive ◽  
R G Roeder
Keyword(s):  
Cell Cycle ◽  
Hela Cell ◽  
Dna Synthesis ◽  
Fold Increase ◽  
S Phase ◽  
Histone Mrna ◽  
Mrna Accumulation ◽  
Histone Mrnas ◽  
The Individual ◽  
Kinetics Of

We have analyzed the kinetics of accumulation of each of the individual core histone mRNAs throughout the HeLa cell cycle in cells synchronized by sequential thymidine and aphidicolin treatments. These analyses showed that during the S phase there was a 15-fold increase in the levels of histone mRNAs and that this resulted from both an increased rate of synthesis and a lengthening of the half-life of histone mRNAs. A comparison of the kinetics of accumulation of histone mRNA in the total cellular and nuclear RNA populations suggested an increased transcription rate through the S phase. Within 30 min after the inhibition of DNA synthesis in mid-S phase, the steady-state concentration and the rate of synthesis of histone mRNA each declined to their non-S-phase levels. Reactivation of histone mRNA accumulation could occur even after an extended mid-S-phase block in DNA synthesis. These results suggest that the mechanisms responsible for histone mRNA synthesis are not restricted to the G1/S boundary of the HeLa cell cycle, but can operate whenever DNA synthesis is occurring.

Identification of a new set of cell cycle-regulatory genes that regulate S-phase transcription of histone genes in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (11) ◽  
pp. 5249-5259 ◽  
Author(s):  
H Xu ◽  
U J Kim ◽  
T Schuster ◽  
M Grunstein
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Replication ◽  
Gene Transcription ◽  
S Phase ◽  
Histone Gene ◽  
Mrna Synthesis ◽  
Histone Mrna ◽  
Complementation Groups ◽  
Histone Gene Transcription

Histone mRNA synthesis is tightly regulated to S phase of the yeast Saccharomyces cerevisiae cell cycle as a result of transcriptional and posttranscriptional controls. Moreover, histone gene transcription decreases rapidly if DNA replication is inhibited by hydroxyurea or if cells are arrested in G1 by the mating pheromone alpha-factor. To identify the transcriptional controls responsible for cycle-specific histone mRNA synthesis, we have developed a selection for mutations which disrupt this process. Using this approach, we have isolated five mutants (hpc1, hpc2, hpc3, hpc4, and hpc5) in which cell cycle regulation of histone gene transcription is altered. All of these mutations are recessive and belong to separate complementation groups. Of these, only one (hpc1) falls in one of the three complementation groups identified previously by other means (M. A. Osley and D. Lycan, Mol. Cell. Biol. 7:4204-4210, 1987), indicating that at least seven different genes are involved in the cell cycle-specific regulation of histone gene transcription. hpc4 is unique in that derepression occurs only in the presence of hydroxyurea but not alpha-factor, suggesting that at least one of the regulatory factors is specific to histone gene transcription after DNA replication is blocked. One of the hpc mutations (hpc2) suppresses delta insertion mutations in the HIS4 and LYS2 loci. This effect allowed the cloning and sequence analysis of HPC2, which encodes a 67.5-kDa, highly charged basic protein.

scholarly journals Phosphorylation of Stem-Loop Binding Protein (SLBP) on Two Threonines Triggers Degradation of SLBP, the Sole Cell Cycle-Regulated Factor Required for Regulation of Histone mRNA Processing, at the End of S Phase

2003 ◽  
Vol 23 (5) ◽  
pp. 1590-1601 ◽  
Author(s):  
Lianxing Zheng ◽  
Zbigniew Dominski ◽  
Xiao-Cui Yang ◽  
Phillip Elms ◽  
Christy S. Raska ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Amino Acids ◽  
Posttranscriptional Regulation ◽  
Binding Protein ◽  
S Phase ◽  
Mrna Processing ◽  
Histone Mrna ◽  
Stem Loop ◽  
Histone Mrnas ◽  
Nuclear Extracts

ABSTRACT The replication-dependent histone mRNAs, the only eukaryotic mRNAs that do not have poly(A) tails, are present only in S-phase cells. Coordinate posttranscriptional regulation of histone mRNAs is mediated by the stem-loop at the 3′ end of histone mRNAs. The protein that binds the 3′ end of histone mRNA, stem-loop binding protein (SLBP), is required for histone pre-mRNA processing and is involved in multiple aspects of histone mRNA metabolism. SLBP is also regulated during the cell cycle, accumulating as cells enter S phase and being rapidly degraded as cells exit S phase. Mutation of any residues in a TTP sequence (amino acids 60 to 62) or mutation of a consensus cyclin binding site (amino acids 99 to 104) stabilizes SLBP in G2 and mitosis. These two threonines are phosphorylated in late S phase, as determined by mass spectrometry (MS) of purified SLBP from late S-phase cells, triggering SLBP degradation. Cells that express a stable SLBP still degrade histone mRNA at the end of S phase, demonstrating that degradation of SLBP is not required for histone mRNA degradation. Nuclear extracts from G1 and G2 cells are deficient in histone pre-mRNA processing, which is restored by addition of recombinant SLBP, indicating that SLBP is the only cell cycle-regulated factor required for histone pre-mRNA processing.

scholarly journals Mammalian Orc1 Protein Is Selectively Released from Chromatin and Ubiquitinated during the S-to-M Transition in the Cell Division Cycle

2002 ◽  
Vol 22 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Cong-Jun Li ◽  
Melvin L. DePamphilis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Schizosaccharomyces Pombe ◽  
Half Life ◽  
S Phase ◽  
Cell Division Cycle ◽  
26S Proteasome ◽  
Selective Dissociation

ABSTRACT Previous studies have shown that changes in the affinity of the hamster Orc1 protein for chromatin during the M-to-G1 transition correlate with the activity of hamster origin recognition complexes (ORCs) and the appearance of prereplication complexes at specific sites. Here we show that Orc1 is selectively released from chromatin as cells enter S phase, converted into a mono- or diubiquitinated form, and then deubiquitinated and re-bound to chromatin during the M-to-G1 transition. Orc1 is degraded by the 26S proteasome only when released into the cytosol, and peptide additions to Orc1 make it hypersensitive to polyubiquitination. In contrast, Orc2 remains tightly bound to chromatin throughout the cell cycle and is not a substrate for ubiquitination. Since the concentration of Orc1 remains constant throughout the cell cycle, and its half-life in vivo is the same as that of Orc2, ubiquitination of non-chromatin-bound Orc1 presumably facilitates the inactivation of ORCs by sequestering Orc1 during S phase. Thus, in contrast to yeast (Saccharomyces cerevisiae and Schizosaccharomyces pombe), mammalian ORC activity appears to be regulated during each cell cycle through selective dissociation and reassociation of Orc1 from chromatin-bound ORCs.

scholarly journals The potency of chitosan-based Pinus merkusii bark extract nanoparticles as anti-cancer on HeLa cell lines

2019 ◽  
Vol 12 (10) ◽  
pp. 1616-1623
Author(s):  
Annise Proboningrat ◽  
Amaq Fadholly ◽  
Regina Purnama Dewi Iskandar ◽  
Agung Budianto Achmad ◽  
Fedik Abdul Rantam ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Hela Cell ◽  
Hela Cells ◽  
Therapeutic Potential ◽  
Bark Extract ◽  
Cytotoxicity Test ◽  
Caspase 9 ◽  
Hela Cell Lines ◽  
Pinus Merkusii

Background and Aim: Cervical cancer accounts for the fourth as a cause of death from cancer in women worldwide, with more than 85% of events and deaths occurring in developing countries. The main problems of chemotherapy are the lack of selectivity and drug resistance. This study aimed to investigate the signal transduction of chitosan-based Pinus merkusii bark extract nanoparticles (Nano-PMBE) as an anticancer on HeLa cell line. Materials and Methods: Nano-PMBE was prepared based on the ionic gelation method. Its anticancer activities in HeLa cells were investigated through cytotoxicity test, cell cycle, and apoptosis analysis. The expression of p53 and caspase-9 was also observed. Results: The results showed that Nano-PMBE has a size of 394.3 nm. Meanwhile, the Nano-PMBE was cytotoxic to HeLa cells ( IC50 of 384.10 μg/ml), caused G0/G1 phase arrest and cell apoptosis in HeLa cells. Besides, the expression of p53 and caspase-9 has increased. Conclusion: The results showed a notable anticancer effect of Nano-PMBE by arresting the cell cycle and inducing apoptosis in HeLa cells, suggesting that it might have therapeutic potential for cervical cancer. Further research is needed to find out more about the anticancer mechanism of Nano-PMBE in HeLa cells to in vivo and clinical studies.

scholarly journals Evaluation of Cytotoxicity and Apoptotic behavior of Cerium Oxide/Zinc Oxide/ Graphene Oxide in HeLa and VERO cell Lines

2021 ◽  
Author(s):  
saranya J ◽  
BS Sre ◽  
M Arivanandan ◽  
K Bhuvaneswari ◽  
S Sherin ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Zinc Oxide ◽  
Graphene Oxide ◽  
Hela Cell ◽  
Cell Line ◽  
Cerium Oxide ◽  
Cell Lines ◽  
Morphological Properties ◽  
Hela Cell Lines ◽  
Anti Cancer

Abstract Using the ultrasonic approach, we produced a morphology involving cerium oxide/ Zinc oxide/graphene oxide (CeO2/ZnO/GO) nanocomposite-based system. The developed nanocomposite was examined using X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM). The average crystallite size was found to be 11.44 nm, as determined by XRD. FTIR analysis was used to confirm the existence of functional groups. FESEM was used to verify the morphological properties of CeO2/ZnO/GO. The micromorphology of CeO2/ZnO/GO nanocomposite reveals a smoother sheet-like structure. In addition, using an antiproliferative assay test, the developed nanosystem was evaluated for its scavenging anti-cancer capability against HeLa cell lines at various doses and incubation intervals. In our investigation, the effective IC50 concentration was reported to be 62.5 µg/ml at 72 h. Further, the developed nanosystem was evaluated for its killing efficacy against normal cell line. To identify apoptosis-associated alterations of cell membranes throughout the apoptosis process, a dual acridine orange/ethidium bromide (AO/EB) fluorescent staining was done using CeO2/ZnO/GO nanocomposite at three specific concentrations. The quantitative analysis was carried out using flow cytometry (FACS study) to determine the cell cycle during which the greatest number of HeLa cells were destroyed. According to the results of the FACS investigation, maximum cell cycle has taken place in P2, P4.As a result, the newly designed CeO2/ZnO/GO hybrid has demonstrated improved anti-cancer efficacy against the HeLa cell line, making it a better therapeutic agent for cervical cancer detection.

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