scholarly journals Regulation of histone mRNA production and stability in serum-stimulated mouse 3T6 fibroblasts.

1983 ◽  
Vol 3 (11) ◽  
pp. 1920-1929 ◽  
Author(s):  
A J DeLisle ◽  
R A Graves ◽  
W F Marzluff ◽  
L F Johnson

We measured the content and metabolism of histone mRNA in mouse 3T6 fibroblasts during a serum-induced transition from the resting to growing state. The content of several histone H3 and H2b mRNAs was measured by an S1 nuclease procedure. All of these increase in parallel by a factor of about 50 during S phase. However, the rate of H3 gene transcription increased only fivefold during this period, as determined in an in vitro transcription assay. This suggests that histone mRNA content is also controlled at the posttranscriptional level. When resting cells were serum stimulated in the presence of cytosine arabinoside, the rate of H3 gene transcription increased to about the same extent as that in control-stimulated cells. However, cytoplasmic H3 mRNA content increased only five to seven-fold. The half-life of H3 mRNA during S phase was about 4 to 5 h. When cytosine arabinoside was added to cells in the S phase, the half-life of the message decreased to about 15 min. The rapid turnover of H3 mRNA was prevented when the drug was added in the presence of cycloheximide or puromycin. The rate of H3 gene transcription decreased by only 35% after treatment with cytosine arabinoside. These results suggest that H3 gene transcription is not tightly coupled to DNA replication but is controlled temporally during the resting to growing transition. However, there is a correlation between the rate of DNA synthesis and the stability of histone H3 mRNA.

1983 ◽  
Vol 3 (11) ◽  
pp. 1920-1929
Author(s):  
A J DeLisle ◽  
R A Graves ◽  
W F Marzluff ◽  
L F Johnson

We measured the content and metabolism of histone mRNA in mouse 3T6 fibroblasts during a serum-induced transition from the resting to growing state. The content of several histone H3 and H2b mRNAs was measured by an S1 nuclease procedure. All of these increase in parallel by a factor of about 50 during S phase. However, the rate of H3 gene transcription increased only fivefold during this period, as determined in an in vitro transcription assay. This suggests that histone mRNA content is also controlled at the posttranscriptional level. When resting cells were serum stimulated in the presence of cytosine arabinoside, the rate of H3 gene transcription increased to about the same extent as that in control-stimulated cells. However, cytoplasmic H3 mRNA content increased only five to seven-fold. The half-life of H3 mRNA during S phase was about 4 to 5 h. When cytosine arabinoside was added to cells in the S phase, the half-life of the message decreased to about 15 min. The rapid turnover of H3 mRNA was prevented when the drug was added in the presence of cycloheximide or puromycin. The rate of H3 gene transcription decreased by only 35% after treatment with cytosine arabinoside. These results suggest that H3 gene transcription is not tightly coupled to DNA replication but is controlled temporally during the resting to growing transition. However, there is a correlation between the rate of DNA synthesis and the stability of histone H3 mRNA.


1984 ◽  
Vol 4 (1) ◽  
pp. 123-132
Author(s):  
R B Alterman ◽  
S Ganguly ◽  
D H Schulze ◽  
W F Marzluff ◽  
C L Schildkraut ◽  
...  

The mechanisms responsible for the periodic accumulation and decay of histone mRNA in the mammalian cell cycle were investigated in mouse erythroleukemia cells, using a cloned mouse H3 histone gene probe that hybridizes with most or all H3 transcripts. Exponentially growing cells were fractionated into cell cycle-specific stages by centrifugal elutriation, a method for purifying cells at each stage of the cycle without the use of treatments that arrest growth. Measurements of H3 histone mRNA content throughout the cell cycle show that the mRNA accumulates gradually during S phase, achieving its highest value in mid-S phase when DNA synthesis is maximal. The mRNA content then decreases as cells approach G2. These results demonstrate that the periodic synthesis of histones during S phase is due to changes in the steady-state level of histone mRNA. They are consistent with the conventional view in which histone synthesis is regulated coordinately with DNA synthesis in the cell cycle. The periodic accumulation and decay of H3 histone mRNA appear to be controlled primarily by changes in the rate of appearance of newly synthesized mRNA in the cytoplasm, determined by pulse-labeling whole cells with [3H]uridine. Measurements of H3 mRNA turnover by pulse-chase experiments with cells in S and G2 did not provide evidence for changes in the cytoplasmic stability of the mRNA during the period of its decay in late S and G2. Furthermore, transcription measurements carried out by brief pulse-labeling in vivo and by in vitro transcription in isolated nuclei indicate that the rate of H3 gene transcription changes to a much smaller extent than the steady-state levels of the mRNA or the appearance of newly synthesized mRNA in the cytoplasm. The results suggest that post-transcriptional processes make an important contribution to the periodic accumulation and decay of histone mRNA and that these processes may operate within the nucleus.


1997 ◽  
Vol 17 (6) ◽  
pp. 3028-3036 ◽  
Author(s):  
R S McLaren ◽  
N Caruccio ◽  
J Ross

Histone mRNA is destabilized at the end of S phase and in cell-free mRNA decay reaction mixtures supplemented with histone proteins, indicating that histones might autoregulate the histone mRNA half-life. Histone mRNA destabilization in vitro requires three components: polysomes, histones, and postpolysomal supernatant (S130). Polysomes are the source of the mRNA and mRNA-degrading enzymes. To investigate the role of the S130 in autoregulation, crude S130 was fractionated by histone-agarose affinity chromatography. Two separate activities affecting the histone mRNA half-life were detected. The histone-agarose-bound fraction contained a histone mRNA destabilizer that was activated by histone proteins; the unbound fraction contained a histone mRNA stabilizer. Further chromatographic fractionation of unbound material revealed only a single protein stabilizer, which was purified to homogeneity, partially sequenced, and found to be La, a well-characterized RNA-binding protein. When purified La was added to reaction mixtures containing polysomes, a histone mRNA decay intermediate was stabilized. This intermediate corresponded to histone mRNA lacking 12 nucleotides from its 3' end and containing an intact coding region. Anti-La antibody blocked the stabilization effect. La had little or no effect on several other cell cycle-regulated mRNAs. We suggest that La prolongs the histone mRNA half-life during S phase and thereby increases histone protein production.


1984 ◽  
Vol 4 (1) ◽  
pp. 123-132 ◽  
Author(s):  
R B Alterman ◽  
S Ganguly ◽  
D H Schulze ◽  
W F Marzluff ◽  
C L Schildkraut ◽  
...  

The mechanisms responsible for the periodic accumulation and decay of histone mRNA in the mammalian cell cycle were investigated in mouse erythroleukemia cells, using a cloned mouse H3 histone gene probe that hybridizes with most or all H3 transcripts. Exponentially growing cells were fractionated into cell cycle-specific stages by centrifugal elutriation, a method for purifying cells at each stage of the cycle without the use of treatments that arrest growth. Measurements of H3 histone mRNA content throughout the cell cycle show that the mRNA accumulates gradually during S phase, achieving its highest value in mid-S phase when DNA synthesis is maximal. The mRNA content then decreases as cells approach G2. These results demonstrate that the periodic synthesis of histones during S phase is due to changes in the steady-state level of histone mRNA. They are consistent with the conventional view in which histone synthesis is regulated coordinately with DNA synthesis in the cell cycle. The periodic accumulation and decay of H3 histone mRNA appear to be controlled primarily by changes in the rate of appearance of newly synthesized mRNA in the cytoplasm, determined by pulse-labeling whole cells with [3H]uridine. Measurements of H3 mRNA turnover by pulse-chase experiments with cells in S and G2 did not provide evidence for changes in the cytoplasmic stability of the mRNA during the period of its decay in late S and G2. Furthermore, transcription measurements carried out by brief pulse-labeling in vivo and by in vitro transcription in isolated nuclei indicate that the rate of H3 gene transcription changes to a much smaller extent than the steady-state levels of the mRNA or the appearance of newly synthesized mRNA in the cytoplasm. The results suggest that post-transcriptional processes make an important contribution to the periodic accumulation and decay of histone mRNA and that these processes may operate within the nucleus.


1992 ◽  
Vol 12 (11) ◽  
pp. 5249-5259 ◽  
Author(s):  
H Xu ◽  
U J Kim ◽  
T Schuster ◽  
M Grunstein

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.


1996 ◽  
Vol 270 (1) ◽  
pp. F164-F169 ◽  
Author(s):  
M. Baum ◽  
M. Amemiya ◽  
V. Dwarakanath ◽  
R. J. Alpern ◽  
O. W. Moe

OKP cells express NHE-3, an amiloride-resistant Na+/H+ antiporter, which is likely an isoform responsible for apical proton secretion by the proximal tubule. We have previously shown that an amiloride-resistant Na+/H+ antiporter in OKP cells is regulated by dexamethasone, a synthetic glucocorticoid. The purpose of the present study was to examine the mechanism for the glucocorticoid-mediated increase in Na+/H+ antiporter activity. Incubation of OKP cells with 10(-6) M dexamethasone resulted in a two- to threefold increase in NHE-3 mRNA abundance. This increase was seen after 4 h of incubation with dexamethasone, a time course similar to that found for Na+/H+ antiporter activity. To examine the mechanism for the increase in NHE-3 mRNA abundance, mRNA half-life and in vitro transcription experiments were performed. NHE-3 mRNA had a half-life of 8 h in control and dexamethasone-treated cells. The rate of in vitro transcription was 1.8-fold greater when OKP cells were treated with dexamethasone. These data suggest that the glucocorticoid-mediated increase in Na+/H+ antiporter activity is due to an increase in NHE-3 gene transcription.


1990 ◽  
Vol 267 (1) ◽  
pp. 241-244 ◽  
Author(s):  
K Saini ◽  
P Thomas ◽  
B Bhandari

In 3T3-L1 adipocytes, glutamine synthetase (GS; EC 6.3.1.2) is subject to regulation by dexamethasone, insulin and dibutyryl cyclic AMP (Bt2cAMP). Dexamethasone increases GS-mRNA content and GS-gene transcription, whereas insulin and Bt2cAMP prevent these increases. The effects of these modulators on the control of GS-mRNA stability were investigated. We report here that GS mRNA has a half-life of about 110 min. Bt2cAMP increases GS-mRNA degradation by greater than 2-fold (half-life 50 min), whereas insulin or dexamethasone have little effect on GS-mRNA stability. Down-regulation of GS-gene expression by Bt2cAMP will involve a co-ordinate response at the level of gene transcription and mRNA stability. However, the molecular mechanisms by which insulin and dexamethasone regulate GS-gene expression in cultured adipocytes remains to be elucidated.


1987 ◽  
Vol 7 (8) ◽  
pp. 2925-2932
Author(s):  
D L Coppock ◽  
A B Pardee

To investigate the mechanism which controls the onset of DNA synthesis, we examined the regulation of thymidine kinase (TK) and its mRNA in the cell cycle. TK activity provides a useful marker for the onset of the S phase in mammalian cells. The present analysis of regulation of TK mRNA in BALB/c 3T3 cells showed that (i) the increase in TK activity depended on the availability of TK mRNA, (ii) the level of TK mRNA between G0 and S increased more than 20-fold, (iii) the rate of run-on TK transcription increased at most 2- to 4-fold between the G0 and S phases, (iv) the half-life of TK mRNA was greater than 8 to 12 h in the S and M phases and decreased as cells entered quiescence, (v) the TK mRNA increase was fully blocked by inhibition of protein synthesis by only 60%, (vi) this inhibition was completely effective for up to about 10 h following serum addition and progressively much less effective when the drugs were added later. These results suggest that the appearance of TK mRNA at the beginning of the S phase in serum-stimulated 3T3 cells is controlled not only by the rate of gene transcription but importantly also by the decreased rate of mRNA degradation. Similar mechanisms may be involved in regulation of the onset of DNA synthesis and the increase in TK mRNA since both are controlled in a manner consistent with a requirement for a labile protein.


2001 ◽  
Vol 21 (19) ◽  
pp. 6484-6494 ◽  
Author(s):  
Laurence Vandel ◽  
Estelle Nicolas ◽  
Olivier Vaute ◽  
Roger Ferreira ◽  
Slimane Ait-Si-Ali ◽  
...  

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.


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