scholarly journals Synergistic activity of Nanog, Pou5f3, and Sox19b establishes chromatin accessibility and developmental competence in a context-dependent manner

2020 ◽  
Author(s):  
Liyun Miao ◽  
Yin Tang ◽  
Ashley R. Bonneau ◽  
Shun Hang Chan ◽  
Mina L. Kojima ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Chromatin Accessibility ◽  
Developmental Competence ◽  
Synergistic Activity ◽  
Large Network ◽  
Dependent Manner ◽  
Motif Analysis ◽  
Triple Mutant ◽  
Context Dependent ◽  
Genome Activation

Genome-wide chromatin reprogramming is a fundamental requirement for establishing developmental competence in the newly-formed zygote. In zebrafish, Nanog, Pou5f3 and Sox19b play partially redundant roles in zygotic genome activation, however their interplay in establishing chromatin competency, the context in which they do so and their mechanism of action remain poorly defined. Here, we generated a triple maternal-zygotic nanog-/-;pou5f3-/-;sox19b-/- mutant and assessed the causal relationship between transcription factor (TF) occupancy, chromatin accessibility and genome activation. Analyses of this triple mutant and combinatorial rescues revealed highly synergistic and context-dependent activity of Nanog, Pou5f3, and Sox19b (NPS) in establishing chromatin competency at >50% of active enhancers. Motif analysis revealed a network of TFs that depend on NPS for establishing chromatin accessibility, including the endodermal determinant Eomesa, whose binding we show is regulated by NPS pioneer-like activity. Finally, we demonstrated that NPS play an essential role in establishing H3K27ac and H3K18ac at enhancers and promoters, and that their function in transcriptional activation can be bypassed by targeted recruitment of histone acetyltransferases to individual genes. Altogether, our findings reveal a large network of TFs that function to establish developmental competency, many of which depend on the synergistic and highly context-dependent role of NPS in establishing chromatin accessibility and regulating histone acetylation in order to activate the genome.

scholarly journals The H3.3 chaperone Hira complex orchestrates oocyte developmental competence

2020 ◽  
Author(s):  
Rowena Smith ◽  
Zongliang Jiang ◽  
Andrej Susor ◽  
Hao Ming ◽  
Janet Tait ◽  
...  
Keyword(s):  
Chromatin Condensation ◽  
Chromatin Accessibility ◽  
Early Embryo ◽  
Early Embryogenesis ◽  
Developmental Competence ◽  
Specific Gene ◽  
Loss Of Function ◽  
Oocyte Developmental Competence ◽  
Zygote Genome Activation ◽  
Genome Activation

AbstractReproductive success relies on a healthy oocyte competent for fertilisation and capable of sustaining early embryo development. By the end of oogenesis, the oocyte is characterised by a transcriptionally silenced state, but the significance of this state and how it is achieved remains poorly understood. Histone H3.3, one of the H3 variants, has unique functions in chromatin structure and gene expression that are cell cycle-independent. We report here a comprehensive characterisation of the roles of the subunits of the Hira complex (i.e. Hira, Cabin1 and Ubn1), which is primarily responsible for H3.3 deposition during mouse oocyte development. Loss-of-function of any component of the Hira complex led to early embryogenesis failure. Transcriptome and nascent RNA analyses revealed that mutant oocytes fail to silence global transcription. Hira complex mutants are unable to establish the H3K4me3 and H3K9me3 repressive marks, resulting in aberrant chromatin accessibility. Among the misregulated genes in mutant oocytes is Zscan4, a 2-cell specific gene that is involved in zygote genome activation. Overexpression of Zscan4 recapitulates the phenotypes of Hira mutants, illustrating that temporal and spatial expression of Zscan4 is fine-tuned at the oocyte-to-embryo transition. Thus, the H3.3 chaperone Hira complex has a maternal effect function in oocyte developmental competence and early embryogenesis by modulating chromatin condensation and transcriptional quiescence.

Antiproliferative and Apoptotic Properties of Andrographolide Against Human Colon Cancer DLD1 Cell Line

2020 ◽  
Vol 20 (6) ◽  
pp. 930-942 ◽  
Author(s):  
Imran Khan ◽  
Sadaf Mahfooz ◽  
Irfan A. Ansari
Keyword(s):  
Colon Cancer ◽  
Cell Line ◽  
Mtt Assay ◽  
Caspase 3 ◽  
Chemotherapeutic Agents ◽  
Synergistic Activity ◽  
Dependent Manner ◽  
Apoptosis Induction ◽  
Dld1 Cell ◽  
Activation Assay

Background: In recent years, natural products have received great attention for cancer prevention owing to their various health benefits, noticeable lack of toxicity and side effects, and the limitations of chemotherapeutic agents. Andrographolide, a labdane diterpenoid is a principal bioactive constituent of Andrographis paniculata Nees, exhibits significant anticancer activity. Objective: The efficacy of andrographolide on colon cancer cells is yet to be elucidated completely. Therefore, we investigated the anticancer efficiency of andrographolide in colon cancer DLD1 cell line. Methods: Antiproliferative activity of andrographolide on DLD1 cells was evaluated by MTT assay, LDH release assay, morphological analysis and colony formation assay. Induction of apoptosis was determined by DAPI staining, Annexin V-FITC staining assay, and caspase-3 activation assay. Role of andrographolide induced cellular reactive oxygen species (ROS) and its association with apoptosis induction in DLD1 cells was elucidated by DCFDA dye. Synergistic ability of andrographolide with 5- fluorouracil (5-FU) and paclitaxel (PTX) was evaluated by MTT assay. Results: Results of the present study indicated that andrographolide declined cell viability of DLD1 cells in a concentration and time-dependent manner. Andrographolide induced apoptosis via nuclear condensation, phosphatidylserine externalization and caspase-3 activation. It also augmented cellular ROS levels which were in turn associated with apoptosis induction in DLD1 cells. Moreover, andrographolide displayed synergistic activity with 5-FU and PTX against DLD1 cells. Conclusion: The present study showed that andrographolide demonstrated antiproliferative and apoptotic properties, moreover it also displayed synergistic effect with chemotherapeutic drugs in colon cancer DLD1 cells.

scholarly journals Disrupting the memory of places induced by drugs of abuse weakens motivational withdrawal in a context-dependent manner

2010 ◽  
Vol 107 (27) ◽  
pp. 12345-12350 ◽  
Author(s):  
S. M. Taubenfeld ◽  
E. V. Muravieva ◽  
A. Garcia-Osta ◽  
C. M. Alberini
Keyword(s):  
Drugs Of Abuse ◽  
Dependent Manner ◽  
Context Dependent

scholarly journals Extracellular Signal-Regulated Kinase Binds to TFII-I and Regulates Its Activation of the c-fosPromoter

2000 ◽  
Vol 20 (4) ◽  
pp. 1140-1148 ◽  
Author(s):  
Dae-Won Kim ◽  
Brent H. Cochran
Keyword(s):  
Map Kinase ◽  
Transcriptional Activation ◽  
Dominant Negative ◽  
Binding Motif ◽  
Dependent Manner ◽  
Consensus Map ◽  
Interaction Domain ◽  
Extracellular Signal

ABSTRACT We have previously shown that TFII-I enhances transcriptional activation of the c-fos promoter through interactions with upstream elements in a signal-dependent manner. Here we demonstrate that activated Ras and RhoA synergize with TFII-I for c-fospromoter activation, whereas dominant-negative Ras and RhoA inhibit these effects of TFII-I. The Mek1 inhibitor, PD98059 abrogates the enhancement of the c-fos promoter by TFII-I, indicating that TFII-I function is dependent on an active mitogen-activated protein (MAP) kinase pathway. Analysis of the TFII-I protein sequence revealed that TFII-I contains a consensus MAP kinase interaction domain (D box). Consistent with this, we have found that TFII-I forms an in vivo complex with extracellular signal-related kinase (ERK). Point mutations within the consensus MAP kinase binding motif of TFII-I inhibit its ability to bind ERK and its ability to enhance the c-fos promoter. Therefore, the D box of TFII-I is required for its activity on the c-fos promoter. Moreover, the interaction between TFII-I and ERK can be regulated. Serum stimulation enhances complex formation between TFII-I and ERK, and dominant-negative Ras abrogates this interaction. In addition, TFII-I can be phosphorylated in vitro by ERK and mutation of consensus MAP kinase substrate sites at serines 627 and 633 impairs the phosphorylation of TFII-I by ERK and its activity on the c-fos promoter. These results suggest that ERK regulates the activity of TFII-I by direct phosphorylation.

scholarly journals Activating Signal Cointegrator 2 Belongs to a Novel Steady-State Complex That Contains a Subset of Trithorax Group Proteins

2003 ◽  
Vol 23 (1) ◽  
pp. 140-149 ◽  
Author(s):  
Young-Hwa Goo ◽  
Young Chang Sohn ◽  
Dae-Hwan Kim ◽  
Seung-Whan Kim ◽  
Min-Jung Kang ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Steady State ◽  
Nuclear Receptors ◽  
Transcriptional Activation ◽  
Retinoic Acid Receptor ◽  
Dependent Manner ◽  
Trithorax Group ◽  
Trithorax Group Proteins

ABSTRACT Many transcription coactivators interact with nuclear receptors in a ligand- and C-terminal transactivation function (AF2)-dependent manner. These include activating signal cointegrator 2 (ASC-2), a recently isolated transcriptional coactivator molecule, which is amplified in human cancers and stimulates transactivation by nuclear receptors and numerous other transcription factors. In this report, we show that ASC-2 belongs to a steady-state complex of approximately 2 MDa (ASC-2 complex [ASCOM]) in HeLa nuclei. ASCOM contains retinoblastoma-binding protein RBQ-3, α/β-tubulins, and trithorax group proteins ALR-1, ALR-2, HALR, and ASH2. In particular, ALR-1/2 and HALR contain a highly conserved 130- to 140-amino-acid motif termed the SET domain, which was recently implicated in histone H3 lysine-specific methylation activities. Indeed, recombinant ALR-1, HALR, and immunopurified ASCOM exhibit very weak but specific H3-lysine 4 methylation activities in vitro, and transactivation by retinoic acid receptor appears to involve ligand-dependent recruitment of ASCOM and subsequent transient H3-lysine 4 methylation of the promoter region in vivo. Thus, ASCOM may represent a distinct coactivator complex of nuclear receptors. Further characterization of ASCOM will lead to a better understanding of how nuclear receptors and other transcription factors mediate transcriptional activation.

scholarly journals Functional Domains of the TOL Plasmid Transcription Factor XylS

2000 ◽  
Vol 182 (4) ◽  
pp. 1118-1126 ◽  
Author(s):  
Niilo Kaldalu ◽  
Urve Toots ◽  
Victor de Lorenzo ◽  
Mart Ustav
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Dependent Manner ◽  
Tol Plasmid ◽  
Terminal Fragment ◽  
Central Regions ◽  
Basic Features ◽  
Regulatory Functions

ABSTRACT The alkylbenzoate degradation genes of Pseudomonas putida TOL plasmid are positively regulated by XylS, an AraC family protein, in a benzoate-dependent manner. In this study, we used deletion mutants and hybrid proteins to identify which parts of XylS are responsible for the DNA binding, transcriptional activation, and benzoate inducibility. We found that a 112-residue C-terminal fragment of XylS binds specifically to the Pm operator in vitro, protects this sequence from DNase I digestion identically to the wild-type (wt) protein, and activates the Pm promoter in vivo. When overexpressed, that C-terminal fragment could activate transcription as efficiently as wt XylS. All the truncations, which incorporated these 112 C-terminal residues, were able to activate transcription at least to some extent when overproduced. Intactness of the 210-residue N-terminal portion was found to be necessary for benzoate responsiveness of XylS. Deletions in the N-terminal and central regions seriously reduced the activity of XylS and caused the loss of effector control, whereas insertions into the putative interdomain region did not change the basic features of the XylS protein. Our results confirm that XylS consists of two parts which probably interact with each other. The C-terminal domain carries DNA-binding and transcriptional activation abilities, while the N-terminal region carries effector-binding and regulatory functions.

A conserved C-terminal sequence that is deleted in v-ErbA is essential for the biological activities of c-ErbA (the thyroid hormone receptor)

1993 ◽  
Vol 13 (6) ◽  
pp. 3675-3685
Author(s):  
F Saatcioglu ◽  
P Bartunek ◽  
T Deng ◽  
M Zenke ◽  
M Karin
Keyword(s):  
Amino Acid ◽  
Thyroid Hormone ◽  
Transcriptional Activation ◽  
Thyroid Hormone Receptor ◽  
Retinoic Acid Receptor ◽  
Biological Activities ◽  
Erythroid Differentiation ◽  
Dependent Manner ◽  
Transcriptional Interference ◽  
Terminal Sequence

The thyroid hormone (T3) receptor type alpha, the c-ErbA alpha proto-oncoprotein, stimulates transcription of T3-dependent promoters, interferes with AP-1 activity, and induces erythroid differentiation in a ligand-dependent manner. The v-ErbA oncoprotein does not bind hormone and has lost all of these activities. Using c-ErbA/v-ErbA chimeras, we found that a deletion of 9 amino acids, conserved among many members of the nuclear receptor superfamily, which are located at the extreme carboxy terminus of c-ErbA alpha is responsible for loss of both transactivation and transcriptional interference activities. Single, double, and triple amino acid substitutions within this region completely abolished T3-dependent transcriptional activation, interference with AP-1 activity, and decreased T3 binding by c-ErbA alpha. However, the lower T3 binding by these mutants does not fully account for the loss of transactivation and transcriptional interference, since a c-ErbA/v-ErbA chimera which was similarly reduced in T3 binding activity has retained both of these functions. Deletion of homologous residues in the retinoic acid receptor alpha (RAR alpha) resulted in a similar loss of transactivation and transcriptional interference activities. The ability of c-ErbA alpha to induce differentiation of transformed erythroblasts is also impaired by all of the mutations introduced into the conserved carboxy-terminal sequence. We conclude that this 9-amino-acid conserved region is essential for normal biological function of c-ErbA alpha and RAR alpha and possibly other T3 and RA receptors.

Progesterone enhances target gene transcription by receptor free of heat shock proteins hsp90, hsp56, and hsp70

1991 ◽  
Vol 11 (10) ◽  
pp. 4998-5004
Author(s):  
M K Bagchi ◽  
S Y Tsai ◽  
M J Tsai ◽  
B W O'Malley
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Shock Protein ◽  
Transcriptional Activation ◽  
Target Gene ◽  
Steroid Hormone ◽  
Receptor Activation ◽  
Target Cells ◽  
Dependent Manner ◽  
Shock Proteins

Steroid receptors regulate transcription of target genes in vivo and in vitro in a steroid hormone-dependent manner. Unoccupied progesterone receptor exists in the low-salt homogenates of target cells as a functionally inactive 8 to 10S complex with several nonreceptor components such as two molecules of 90-kDa heat shock protein (hsp90), a 70-kDa heat shock protein (hsp70), and a 56-kDa heat shock protein (hsp56). Ligand-induced dissociation of receptor-associated proteins such as hsp90 has been proposed as the mechanism of receptor activation. Nevertheless, it has not been established whether, beyond release of heat shock proteins, the steroidal ligand plays a role in modulating receptor activity. To examine whether the release of these nonreceptor proteins from receptor complex results in a constitutively active receptor, we isolated an unliganded receptor form essentially free of hsp90, hsp70, and hsp56. Using a recently developed steroid hormone-responsive cell-free transcription system, we demonstrate for the first time that the dissociation of heat shock proteins is not sufficient to generate a functionally active receptor. This purified receptor still requires hormone for high-affinity binding to a progesterone response element and for efficient transcriptional activation of a target gene. When an antiprogestin, Ru486, is bound to the receptor, it fails to promote efficient transcription. We propose that in the cell, in addition to the release of receptor-associated inhibitory proteins, a distinct hormone-mediated activation event must precede efficient gene activation.

scholarly journals A Novel Transcriptional Repression Domain Mediates p21WAF1/CIP1 Induction of p300 Transactivation

2000 ◽  
Vol 20 (8) ◽  
pp. 2676-2686 ◽  
Author(s):  
Andrew W. Snowden ◽  
Lisa A. Anderson ◽  
Gill A. Webster ◽  
Neil D. Perkins
Keyword(s):  
Cell Cycle ◽  
Transcriptional Activation ◽  
Transcriptional Repression ◽  
Kinase Inhibitor ◽  
Core Promoter ◽  
Dependent Manner ◽  
Creb Binding Protein ◽  
Cycle Dependent ◽  
Repression Domain

ABSTRACT The transcriptional coactivators p300 and CREB binding protein (CBP) are important regulators of the cell cycle, differentiation, and tumorigenesis. Both p300 and CBP are targeted by viral oncoproteins, are mutated in certain forms of cancer, are phosphorylated in a cell cycle-dependent manner, interact with transcription factors such as p53 and E2F, and can be found complexed with cyclinE-Cdk2 in vivo. Moreover, p300-deficient cells show defects in proliferation. Here we demonstrate that transcriptional activation by both p300 and CBP is stimulated by coexpression of the cyclin-dependent kinase inhibitor p21WAF/CIP1. Significantly this stimulation is independent of both the inherent histone acetyltransferase (HAT) activity of p300 and CBP and of the previously reported carboxyl-terminal binding site for cyclinE-Cdk2. Rather, we describe a previously uncharacterized transcriptional repression domain (CRD1) within p300. p300 transactivation is stimulated through derepression of CRD1 by p21. Significantly p21 regulation of CRD1 is dependent on the nature of the core promoter. We suggest that CRD1 provides a novel mechanism through which p300 and CBP can switch activities between the promoters of genes that stimulate growth and those that enhance cell cycle arrest.

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