scholarly journals 134INCOMPLETE HISTONE ACETYLATION OF SOMATIC CHROMATIN IN BOVINE OOCYTES

2004 ◽  
Vol 16 (2) ◽  
pp. 189
Author(s):  
G. Wee ◽  
S.-H. Kim ◽  
K.P. Kim ◽  
S. Yeo ◽  
D.-B. Koo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Somatic Cell ◽  
Histone Acetylation ◽  
Transcriptional Activation ◽  
Linear Models ◽  
Trichostatin A ◽  
Specific Inhibitor ◽  
Early Embryo ◽  
Image Analyzer ◽  
Cell Nuclei

Histone acetylation as an important regulatory mechanism of chromatin structure preceeding zygotic gene expression in early embryo development. After fertilization, transcriptional activation of the embryo begins during the S/G2 phase of the first cell cycle. However, the precise mechanism underlying activation of zygotic transcription remains to be understood, especially in bovine nuclear transfer (NT) embryos. It is known that acetylation of histone H4 lysine 5 (H4K5) represents hyperacetylation state, which is correlated with gene expression. In this study, the acetylation of H4K5 was observed during pronuclear formation by using immunofluorescence analysis with anti-AcH4K5. Our data were analyzed by the general linear models (GLM) procedure of the SAS. In IVF embryos, acetylation of H4K5 occurred on the paternal chromatin at 8h after fertilization but did not occur on the maternal chromatin until 10h after fertilization. Reconstructed oocytes with deactylated somatic cell nuclei began to show signs of acetylation on chromatin at 3h after fusion. When acetylation intensity was calculated using an image analyzer, IVF embryos presented a higher acetylation signal than NT embryos (P<0.05). To induce hyperacetylation in NT embryos, somatic cells were exposed to trichostatin A (TSA, 1μM for 60h), a specific inhibitor of histone deacetylase (HDAC), prior to NT. Acetylated signals of H4K5 increased significantly in TSA-treated cells as compared with non-treated cells (P<0.05). The reconstructed embryos with TSA-treated cells showed a higher fluorescence intensity than the oocytes with non-treated cells (P<0.05), but weak signals compared to IVF embryos. Thus, the results demonstrated low histone acetylation level of somatic cell nuclei after NT during the zygotic progress. Our findings suggest that developmental failures of NT embryos may be due to incomplete chromatin remodeling of somatic cell nuclei during early embryonic development.

scholarly journals Changes in histone acetylation during mouse oocyte meiosis

2003 ◽  
Vol 162 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Jin-Moon Kim ◽  
Honglin Liu ◽  
Mayuko Tazaki ◽  
Masao Nagata ◽  
Fugaku Aoki
Keyword(s):  
Gene Expression ◽  
Histone Acetylation ◽  
Expression Pattern ◽  
Trichostatin A ◽  
Gene Expression Pattern ◽  
Specific Inhibitor ◽  
Preimplantation Embryos ◽  
Global Changes ◽  
Cell Nuclei ◽  
Oocyte Meiosis

We examined global changes in the acetylation of histones in mouse oocytes during meiosis. Immunocytochemistry with specific antibodies against various acetylated lysine residues on histones H3 and H4 showed that acetylation of all the lysines decreased to undetectable or negligible levels in the oocytes during meiosis, whereas most of these lysines were acetylated during mitosis in preimplantation embryos and somatic cells. When the somatic cell nuclei were transferred into enucleated oocytes, the acetylation of lysines decreased markedly. This type of deacetylation was inhibited by trichostatin A, a specific inhibitor of histone deacetylase (HDAC), thereby indicating that HDAC is able to deacetylate histones during meiosis but not during mitosis. Meiosis-specific deacetylation may be a consequence of the accessibility of HDAC1 to the chromosome, because HDAC1 colocalized with the chromosome during meiosis but not during mitosis. As histone acetylation is thought to play a role in propagating the gene expression pattern to the descendent generation during mitosis, and the gene expression pattern of differentiated oocytes is reprogrammed during meiosis to allow the initiation of a new program by totipotent zygotes of the next generation, our results suggest that the oocyte cytoplasm initializes a program of gene expression by deacetylating histones.

scholarly journals BIX-01294 increases pig cloning efficiency by improving epigenetic reprogramming of somatic cell nuclei

Reproduction ◽  
2016 ◽  
Vol 151 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Jiaojiao Huang ◽  
Hongyong Zhang ◽  
Jing Yao ◽  
Guosong Qin ◽  
Feng Wang ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Histone Acetylation ◽  
Methylation Status ◽  
Specific Inhibitor ◽  
Epigenetic Reprogramming ◽  
Developmental Competence ◽  
Abnormal Development ◽  
Aberrant Methylation ◽  
Cell Nuclei

Accumulating evidence suggests that faulty epigenetic reprogramming leads to the abnormal development of cloned embryos and results in the low success rates observed in all mammals produced through somatic cell nuclear transfer (SCNT). The aberrant methylation status of H3K9me and H3K9me2 has been reported in cloned mouse embryos. To explore the role of H3K9me2 and H3K9me in the porcine somatic cell nuclear reprogramming, BIX-01294, known as a specific inhibitor of G9A (histone-lysine methyltransferase of H3K9), was used to treat the nuclear-transferred (NT) oocytes for 14–16 h after activation. The results showed that the developmental competence of porcine SCNT embryos was significantly enhanced bothin vitro(blastocyst rate 16.4% vs 23.2%,P<0.05) andin vivo(cloning rate 1.59% vs 2.96%) after 50 nm BIX-01294 treatment. BIX-01294 treatment significantly decreased the levels of H3K9me2 and H3K9me at the 2- and 4-cell stages, which are associated with embryo genetic activation, and increased the transcriptional expression of the pluripotency genesSOX2,NANOGandOCT4in cloned blastocysts. Furthermore, the histone acetylation levels of H3K9, H4K8 and H4K12 in cloned embryos were decreased after BIX-01294 treatment. However, co-treatment of activated NT oocytes with BIX-01294 and Scriptaid rescued donor nuclear chromatin from decreased histone acetylation of H4K8 that resulted from exposure to BIX-01294 only and consequently improved the preimplantation development of SCNT embryos (blastocyst formation rates of 23.7% vs 21.5%). These results indicated that treatment with BIX-01294 enhanced the developmental competence of porcine SCNT embryos through improvements in epigenetic reprogramming and gene expression.

Trichostatin A affects histone acetylation and gene expression in porcine somatic cell nucleus transfer embryos

2009 ◽  
Vol 72 (8) ◽  
pp. 1097-1110 ◽  
Author(s):  
R.P. Cervera ◽  
N. Martí-Gutiérrez ◽  
E. Escorihuela ◽  
R. Moreno ◽  
M. Stojkovic
Keyword(s):  
Gene Expression ◽  
Somatic Cell ◽  
Histone Acetylation ◽  
Cell Nucleus ◽  
Trichostatin A ◽  
Somatic Cell Nucleus ◽  
Nucleus Transfer ◽  
Somatic Cell Nucleus Transfer

scholarly journals Potentiation of androgen receptor transcriptional activity by inhibition of histone deacetylation--rescue of transcriptionally compromised mutants

2004 ◽  
Vol 182 (3) ◽  
pp. 377-389 ◽  
Author(s):  
CG Korkmaz ◽  
K Fronsdal ◽  
Y Zhang ◽  
PI Lorenzo ◽  
F Saatcioglu
Keyword(s):  
Androgen Receptor ◽  
Histone Acetylation ◽  
Nuclear Receptor ◽  
Transcriptional Activation ◽  
Transcriptional Activity ◽  
Trichostatin A ◽  
Specific Antigen ◽  
Histone Deacetylation ◽  
Lncap Cells ◽  
Viral Oncoprotein

Androgens are critical in the development and maintenance of the male reproductive system and important in the progression of prostate cancer. The effects of androgens are mediated by the androgen receptor (AR), which is a ligand-modulated transcription factor that belongs to the nuclear receptor superfamily. We and others have previously shown that CREB-binding protein (CBP) can function as a coactivator for AR. Similar to some other nuclear receptor coactivators and/or the proteins that they interact with, CBP has histone acetyl transferase (HAT) activity that is thought to contribute to transcriptional activation by nuclear receptors. We have therefore assessed whether an increase in the histone acetylation status in the cell can influence AR transcriptional activity, by using the histone deacetylase (HDAC) inhibitors (HDACIs) trichostatin A (TSA), sodium butyrate (Na-But) and depsipeptide (FR901228). We found that inhibition of HDAC activity significantly increased the ability of endogenous AR in LNCaP cells, or ectopically expressed AR in HeLa cells, to activate transcription from AR-dependent reporter constructs. In addition, HDACIs increased the androgen-dependent activation of the prostate-specific antigen (PSA) gene in LNCaP cells, an increase that was not due to an increase in nuclear AR protein levels. Moreover, the viral oncoprotein E1A that inhibits CBP HAT activity fully repressed the ability of HDACIs to stimulate AR-mediated transcription, indicating that CBP is involved in this process. Deletional mutagenesis of AR indicated that whereas the AF-2 domain in the C-terminus is dispensable, the AF-1 domain in the N-terminus is required for augmentation of AR action by HDACIs, an observation which is in concordance with the reduced ability of CBP to activate AR N-terminal deletion mutants. Furthermore, HDACI treatment rescued the deficiency in the transactivation potential of AF-2 mutants. Taken together, our findings suggest that a change in the level of histone acetylation of target genes is an important determinant of AR action, possibly mediated by CBP.

scholarly journals PfGCN5-Mediated Histone H3 Acetylation Plays a Key Role in Gene Expression in Plasmodium falciparum

2007 ◽  
Vol 6 (7) ◽  
pp. 1219-1227 ◽  
Author(s):  
Long Cui ◽  
Jun Miao ◽  
Tetsuya Furuya ◽  
Xinyi Li ◽  
Xin-zhuan Su ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plasmodium Falciparum ◽  
Histone Acetylation ◽  
Transcriptional Activation ◽  
Histone H3 ◽  
Epigenetic Mechanism ◽  
Promoter Regions ◽  
Specific Expression ◽  
Transcriptional Initiation ◽  
Translational Start

ABSTRACT Histone acetylation, regulated by the opposing actions of histone acetyltransferases (HATs) and deacetylases, is an important epigenetic mechanism in eukaryotic transcription. Although an acetyltransferase (PfGCN5) has been shown to preferentially acetylate histone H3 at K9 and K14 in Plasmodium falciparum, the scale of histone acetylation in the parasite genome and its role in transcriptional activation are essentially unknown. Using chromatin immunoprecipitation (ChIP) and DNA microarray, we mapped the global distribution of PfGCN5, histone H3K9 acetylation (H3K9ac) and trimethylation (H3K9m3) in the P. falciparum genome. While the chromosomal distributions of H3K9ac and PfGCN5 were similar, they are radically different from that of H3K9m3. In addition, there was a positive, though weak correlation between relative occupancy of H3K9ac on individual genes and the levels of gene expression, which was inversely proportional to the distance of array elements from the putative translational start codons. In contrast, H3K9m3 was negatively correlated with gene expression. Furthermore, detailed mapping of H3K9ac for selected genes using ChIP and real-time PCR in three erythrocytic stages detected stage-specific peak H3K9ac enrichment at the putative transcriptional initiation sites, corresponding to stage-specific expression of these genes. These data are consistent with H3K9ac and H3K9m3 as epigenetic markers of active and silent genes, respectively. We also showed that treatment with a PfGCN5 inhibitor led to reduced promoter H3K9ac and gene expression. Collectively, these results suggest that PfGCN5 is recruited to the promoter regions of genes to mediate histone acetylation and activate gene expression in P. falciparum.

scholarly journals Histone deacetylase inhibitors suppress IL-2–mediated gene expression prior to induction of apoptosis

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1490-1495 ◽  
Author(s):  
Yuko Koyama ◽  
Masaaki Adachi ◽  
Masuo Sekiya ◽  
Mutsuhiro Takekawa ◽  
Kohzoh Imai
Keyword(s):  
Gene Expression ◽  
Histone Deacetylase ◽  
Transcriptional Activation ◽  
Histone Deacetylase Inhibitors ◽  
Trichostatin A ◽  
Hdac Inhibitors ◽  
K562 Cells ◽  
Histone Hyperacetylation ◽  
Induced Apoptosis ◽  
Do So

Histone deacetylase (HDAC) inhibitors can induce transcriptional activation of a number of genes and induce cellular differentiation as histone acetylation levels increase. Although these inhibitors induce apoptosis in several cell lines, the precise mechanism by which they do so remains obscure. This study shows that HDAC inhibitors, sodium butyrate and trichostatin A (TSA), abrogate interleukin (IL)-2–mediated gene expression in IL-2–dependent cells. The HDAC inhibitors readily induced apoptosis in IL-2–dependent ILT-Mat cells and BAF-B03 transfectants expressing the IL-2 receptor βc chain, whereas they induced far less apoptosis in cytokine-independent K562 cells. However, these inhibitors similarly increased acetylation levels of histones in both cells. Although histone hyperacetylation is believed to lead to transcriptional activation, the results showed an abrogation of IL-2–mediated induction of c-myc,bag-1, and LC-PTP gene expression. This observed abrogation of gene expression occurred prior to phosphatidylserine externalization, a process that occurs in early apoptotic cells. Considering the biologic role played by IL-2–mediated gene expression in cell survival, these data suggest that its abrogation may contribute to the apoptotic process induced by HDAC inhibitors.

20 ALTERED GENE EXPRESSION IN BOVINE SOMATIC CELL NUCLEAR-TRANSFERRED EMBRYOS AFTER TRICHOSTATIN A TREATMENT

2012 ◽  
Vol 24 (1) ◽  
pp. 121
Author(s):  
L. S. A. Camargo ◽  
M. M. Pereira ◽  
S. Wohlres-Viana ◽  
C. R. C. Quintão ◽  
L. T. Iguma ◽  
...  
Keyword(s):  
Gene Expression ◽  
Somatic Cell ◽  
Chromatin Remodeling ◽  
Relative Abundance ◽  
Glucose Transporter ◽  
Trichostatin A ◽  
Rna Extraction ◽  
Calf Serum ◽  
Glucose Transporter 1

Trichostatin A is a histone deacetylase inhibitor that improves histone acetylation and chromatin remodeling of somatic cell nuclear-transferred embryos (Iager et al. 2008 Cloning Stem Cells 10, 371–379; Maalouf et al. 2009 BMC Dev. Biol. 9, 11). We have previously observed that it also improves quality of bovine cloned embryos, which may increase pregnancy rates. This study aimed to evaluate the effect of trichostatin A treatment of zygotes on relative abundance of 9 transcripts in bovine nuclear-transferred blastocysts. In vitro matured oocytes were enucleated, fused to somatic cells and activated with ionomycin (Camargo et al. 2011 Reprod. Fertil. Dev. 23, 122). After activation, putative zygotes were randomly separated into 2 groups: NT-TRICHO, zygotes were cultured for 4 h in 6-DMAP followed by 7 h in CR2 aa medium plus with 2.5% fetal calf serum (FCS; Nutricell, Campinas, Brazil), both supplemented with 50 nM trichostatin A (Sigma); NT-CONT, zygotes were cultured in the same described conditions without thichostatin A supplementation. In vitro-fertilized embryos (IVF group) were used as a calibrator for relative transcript quantification. Embryos from the 3 groups were cultured in CR2 aa supplemented with 2.5% FCS under 5% CO2, 5% O2 and 90% N2 at 38.5°C. At 168 h postactivation, the embryos were rapidly frozen in liquid nitrogen. Pools of 10 blastocysts for each group were subject to RNA extraction and reverse transcription, in which cDNA was amplified by real-time PCR using the β-actin and GAPDH genes as endogenous references. The transcripts analysed encode high mobility group N1 (HMGN1), peroxiredoxin 1 (PRDX1), octamer-binding protein 4 (OCT4), insulin-like growth factor 1 and 2 receptors (IGF1r and IGF2r), glucose transporter 1 and 5 (GLUT1 and GLUT5), histone acetyltransferase (HAT) and heat shock protein 70.1 (HSP70) genes. Results were analysed by a pair-wise fixed reallocation randomization test using the REST software v.2. Data from NT-TRICHO and NT-CONT were compared with the IVF group and between themselves. The relative abundance of HSP70, PRDX1, IGF2r and HMGN1 transcripts was higher (P < 0.05) in NT-TRICHO compared with the IVF group and no difference was detected for the other transcripts. In the NT-CONT group, the relative abundance of IGF2r and HAT was higher (P < 0.05), whereas IGF1r and OCT4 were lower (P < 0.05) compared with IVF embryos. When data from NT-TRICHO and NT-CONT were compared, a higher amount (P < 0.05) of stress-associated transcripts (HSP70 and PRDX1) were found in NT-TRICO blastocysts. These results suggest that although trichostatin A may improve chromatin remodeling, alterations on gene expression still persist in bovine somatic cell nuclear-transferred blastocysts in comparison with IVF embryos. Financial support: Embrapa Project 01.07.01.002, CNPq 403019/2008–7 and Fapemig.

Thrombopoietin regulates IEX-1 gene expression through ERK-induced AML1 phosphorylation

Blood ◽  
2006 ◽  
Vol 107 (8) ◽  
pp. 3106-3113 ◽  
Author(s):  
Virginie Hamelin ◽  
Claire Letourneux ◽  
Paul-Henri Romeo ◽  
Françoise Porteu ◽  
Murielle Gaudry
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Transcriptional Activity ◽  
Specific Inhibitor ◽  
Early Gene ◽  
Gm Csf ◽  
Extracellular Signal ◽  
Macrophage Colony Stimulating Factor ◽  
Macrophage Colony ◽  
Stimulating Factor

Abstract The extracellular signal-regulated kinases (ERKs) are required for thrombopoietin (TPO) functions on hematopoietic cells, but the ERKs targets involved remain unknown. Here we show that the regulation of the immediate early gene X-1 (IEX-1), identified as an ERK substrate in response to TPO, was mediated by an ERK-dependent phosphorylation of AML1. The addition of TPO to UT7-Mpl cells and primary megakaryocytes induced gene expression of IEX-1. Neither erythropoietin (EPO) nor granulocyte macrophage-colony stimulating factor (GM-CSF) was able to activate IEX-1 gene expression in UT7-Mpl cells. The induced expression was mediated by a transcriptional activation of the IEX-1 promoter and required an AML1-binding site located at –1068. The direct involvement of AML1 in the regulation of IEX-1 gene expression was shown by both the use of AML1 mutants and by shRNA experiments targeting endogenous AML1. Finally, the ability of TPO to induce the IEX-1 gene expression was inhibited by U0126, a specific inhibitor of the ERKs activator MEK and AML1 transcriptional activity was shown to be modulated by TPO through ERK-dependent phosphorylation. Taken together, these data suggest that AML1 plays a role in modulating the IEX-1 expression and that the ERK-dependent AML1 phosphorylation regulates the TPO-mediated activation of IEX-1.

Kinetic analysis of histone acetylation turnover and Trichostatin A induced hyper- and hypoacetylation in alfalfa

2002 ◽  
Vol 80 (3) ◽  
pp. 279-293 ◽  
Author(s):  
Jakob H Waterborg ◽  
Tamás Kapros
Keyword(s):  
Gene Expression ◽  
Steady State ◽  
Histone Acetylation ◽  
Histone Deacetylases ◽  
Trichostatin A ◽  
Similar Rate ◽  
Lysine Methylation ◽  
Histone H2a ◽  
Turnover Rates

Dynamic histone acetylation is a characteristic of chromatin transcription. The first estimates for the rate of acetylation turnover of plants are reported, measured in alfalfa cells by pulse, pulse-chase, and steady-state acetylation labeling. Acetylation turnover half-lives of about 0.5 h were observed by all methods used for histones H3, H4, and H2B. This is consistent with the rate at which changes in gene expression occur in plants. Treatment with histone deacetylase inhibitor Trichostatin A (TSA) induced hyperacetylation at a similar rate. Replacement histone variant H3.2, preferentially localized in highly acetylated chromatin, displayed faster acetyl turnover. Histone H2A with a low level of acetylation was not subject to rapid turnover or hyperacetylation. Patterns of acetate labeling revealed fundamental differences between histone H3 versus histones H4 and H2B. In H3, acetylation of all molecules, limited by lysine methylation, had similar rates, independent of the level of lysine acetylation. Acetylation of histones H4 and H2B was seen in only a fraction of all molecules and involved multiacetylation. Acetylation turnover rates increased from mono- to penta- and hexaacetylated forms, respectively. TSA was an effective inhibitor of alfalfa histone deacetylases in vivo and caused a doubling in steady-state acetylation levels by 4–6 h after addition. However, hyperacetylation was transient due to loss of TSA inhibition. TSA-induced overexpression of cellular deacetylase activity produced hypoacetylation by 18 h treatment with enhanced acetate turnover labeling of alfalfa histones. Thus, application of TSA to change gene expression in vivo in plants may have unexpected consequences.

Sign in / Sign up

Export Citation Format

Share Document