scholarly journals Securin overexpression correlates with the activated Rb/E2F1 pathway and histone H3 epigenetic modifications in raw areca nut-induced carcinogenesis in mice

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Nabamita Boruah ◽  
Chongtham Sovachandra Singh ◽  
Pooja Swargiary ◽  
Hughbert Dkhar ◽  
Anupam Chatterjee
Keyword(s):  
Gastric Cancer ◽  
Transcriptional Activation ◽  
Promoter Region ◽  
Chromosomal Instability ◽  
Core Promoter ◽  
Histone H3 ◽  
Subsequent Development ◽  
Treated Group ◽  
Areca Nut ◽  
Induced Changes

Abstract Background Raw areca nut (RAN) consumption induces oral, esophageal and gastric cancers, which are significantly associated with the overexpression of pituitary tumor transforming gene 1/securin and chromosomal instability (CIN). An association of Securin/PTTG1 upregulation and gastric cancer in human was also demonstrated earlier. Since the molecular mechanism underlying securin upregulation remains unclear, this study intended to investigate the association of securin upregulation with the Rb-E2F1 circuit and epigenetic histone (H3) modification patterns both globally and in the promoter region of the securin gene. Methods Six groups of mice were used, and in the treated group, each mouse consumed 1 mg of RAN extract with lime per day ad libitum in the drinking water for 60 days, after which the dose was increased by 1 mg every 60 days. Histopathological evaluation of stomach tissues was performed and securin expression was analysed by immunoblotting as well as by immunohistochemistry. ChIP-qPCR assays were performed to evaluate the recruitment of different histone modifications in the core promoter region of securin gene as well as its upstream and downstream regions. Results All mice developed gastric cancer with securin overexpression after 300 days of feeding. Immunohistochemistry data revealed hyperphosphorylation of Rb and upregulation of E2F1 in the RAN-treated samples. Increased trimethylation of H3 lysine 4 and acetylation of H3 lysine 9 and 18 both globally and in the promoter region of the securin gene were observed by increasing the levels of lysine-N-methyltransferase 2A, lysine-acetyltransferase, EP-300 and PCAF after RAN treatment. ChIP-qPCR data revealed that the quantity of DNA fragments retrieved from the immunoprecipitated samples was maximum in the -83 to -192 region than further upstream and the downstream of the promoter for H3K4Me3, H3K9ac, H3K18ac and H3K9me3. Conclusions RAN-mediated pRb-inactivation induced securin upregulation, a putative E2F1 target, by inducing misregulation in chromatin remodeling in its promoter region, which led to transcriptional activation and subsequent development of chromosomal instability. Therefore, present results have led to the hypothesis that RAN-induced changes in the epigenetic landscape, securin overexpression and subsequent elevation of chromosomal instability is probably byproducts of inactivation of the pRb pathway.

scholarly journals Securin overexpression correlates with the activated Rb/E2F1 pathway and Histone H3 epigenetic modifications in raw areca-nut induced carcinogenesis in mice

2021 ◽  
Author(s):  
Nabamita Boruah ◽  
Chongtham Sovachandra Singh ◽  
Pooja Swargiary ◽  
Hughbert Dakhar ◽  
Anupam Chatterjee
Keyword(s):  
Chromatin Remodeling ◽  
Transcriptional Activation ◽  
Promoter Region ◽  
Chromosomal Instability ◽  
Histone H3 ◽  
Treated Group ◽  
Areca Nut ◽  
Epigenetic Landscape ◽  
Lysine Acetyltransferase ◽  
Induced Changes

Abstract Background Raw areca-nut (RAN) consumption induces oral, esophageal and gastric cancers which are significantly associated with the overexpression of pituitary tumor transforming gene1/Securin and chromosomal instability (CIN). Since the molecular mechanism underlying Securin upregulation remains unclear, this study is intended to investigate the association of Securin upregulation with Rb-E2F1 circuit and epigenetic histone (H3) modifications pattern both globally and in the promoter region of Securin gene. Methods Six groups of mice were used and in the treated group each mouse consumed 1 mg of RAN-extract with lime per day ad libitum in the drinking water for 60 days after which the dose was increased by 1 mg after every 60 days. Histopathological evaluation of stomach tissues was done and Securin expression was analysed by immunoblotting as well as by immunohistochemistry. ChIP-qPCR assay was performed for evaluating the recruitment of different histone modifications in the two regions of Securin promoter. Results All mice developed gastric cancer with Securin overexpression after 300 days of feeding. Immunohistochemistry data revealed hyperphosphorylation of Rb and upregulation of E2F1 in the RAN-treated samples. Increased trimethylation of H3 Lysine4 and acetylation of H3 Lysine9 and 18 both globally and in the promoter region of Securin gene was observed by increasing the level of lysine-N-methyltransferase2A, lysine-acetyltransferase, EP-300 and PCAF after RAN-treatment. ChIP-qPCR data show an increased recruitment of H3K4me3, H3K9ac and H3K18ac in the promoter of Securin gene after RAN-exposure Conclusions In light of the present results, it seems that RAN-mediated pRb-inactivation induced Securin upregulation, a putative E2F1 target, by inducing misregulation in chromatin remodeling in its promoter region which led to transcriptional activation and subsequently develop chromosomal instability. Therefore, the present results have led to the hypothesis that RAN-induced changes in the epigenetic landscape, Securin overexpression and subsequent elevation of chromosomal instability are probably a by-product of the inactivation of the pRb pathway.

scholarly journals The Core Promoter Is a Regulatory Hub for Developmental Gene Expression

2021 ◽  
Vol 9 ◽  
Author(s):  
Anna Sloutskin ◽  
Hila Shir-Shapira ◽  
Richard N. Freiman ◽  
Tamar Juven-Gershon
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Transcription Initiation ◽  
Promoter Region ◽  
Core Promoter ◽  
Developmental Gene ◽  
Core Promoter Region ◽  
Developmental Gene Expression ◽  
The Core ◽  
Regulatory Module

The development of multicellular organisms and the uniqueness of each cell are achieved by distinct transcriptional programs. Multiple processes that regulate gene expression converge at the core promoter region, an 80 bp region that directs accurate transcription initiation by RNA polymerase II (Pol II). In recent years, it has become apparent that the core promoter region is not a passive DNA component, but rather an active regulatory module of transcriptional programs. Distinct core promoter compositions were demonstrated to result in different transcriptional outputs. In this mini-review, we focus on the role of the core promoter, particularly its downstream region, as the regulatory hub for developmental genes. The downstream core promoter element (DPE) was implicated in the control of evolutionarily conserved developmental gene regulatory networks (GRNs) governing body plan in both the anterior-posterior and dorsal-ventral axes. Notably, the composition of the basal transcription machinery is not universal, but rather promoter-dependent, highlighting the importance of specialized transcription complexes and their core promoter target sequences as key hubs that drive embryonic development, differentiation and morphogenesis across metazoan species. The extent of transcriptional activation by a specific enhancer is dependent on its compatibility with the relevant core promoter. The core promoter content also regulates transcription burst size. Overall, while for many years it was thought that the specificity of gene expression is primarily determined by enhancers, it is now clear that the core promoter region comprises an important regulatory module in the intricate networks of developmental gene expression.

scholarly journals CRISPR-based transcriptional activation tool for silent genes in filamentous fungi

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
László Mózsik ◽  
Mirthe Hoekzema ◽  
Niels A. W. de Kok ◽  
Roel A. L. Bovenberg ◽  
Yvonne Nygård ◽  
...  
Keyword(s):  
Filamentous Fungi ◽  
Transcriptional Activation ◽  
Core Promoter ◽  
Crop Protection ◽  
Gene Clusters ◽  
Growth Conditions ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Fluorescent Reporter ◽  
A Genome

AbstractFilamentous fungi are historically known to be a rich reservoir of bioactive compounds that are applied in a myriad of fields ranging from crop protection to medicine. The surge of genomic data available shows that fungi remain an excellent source for new pharmaceuticals. However, most of the responsible biosynthetic gene clusters are transcriptionally silent under laboratory growth conditions. Therefore, generic strategies for activation of these clusters are required. Here, we present a genome-editing-free, transcriptional regulation tool for filamentous fungi, based on the CRISPR activation (CRISPRa) methodology. Herein, a nuclease-defective mutant of Cas9 (dCas9) was fused to a highly active tripartite activator VP64-p65-Rta (VPR) to allow for sgRNA directed targeted gene regulation. dCas9-VPR was introduced, together with an easy to use sgRNA “plug-and-play” module, into a non-integrative AMA1-vector, which is compatible with several filamentous fungal species. To demonstrate its potential, this vector was used to transcriptionally activate a fluorescent reporter gene under the control of the penDE core promoter in Penicillium rubens. Subsequently, we activated the transcriptionally silent, native P. rubens macrophorin biosynthetic gene cluster by targeting dCas9-VPR to the promoter region of the transcription factor macR. This resulted in the production of antimicrobial macrophorins. This CRISPRa technology can be used for the rapid and convenient activation of silent fungal biosynthetic gene clusters, and thereby aid in the identification of novel compounds such as antimicrobials.

scholarly journals Apoptotic mechanisms of gastric cancer cells induced by isolated Erinacine S through epigenetic histone H3 methylation of FasL and TRAIL

2021 ◽  
Author(s):  
Hsing-Chun Kuo ◽  
Shui-Yi Tung ◽  
Ko-Chao Lee ◽  
Kam-Fai Lee ◽  
Ya-Ling Yang ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cancer Cells ◽  
Histone H3 ◽  
Ethanol Extract ◽  
Gastric Cancer Cells ◽  
Hericium Erinaceus ◽  
Histone H3 Methylation ◽  
Health Promoting ◽  
Great Health

Erinacine S, the new bioactive diterpenoid compound isolated from the ethanol extract of the mycelia of Hericium erinaceus, displays great health-promoting properties. However, the effects of erinacine S on inductive...

scholarly journals The core promoter region of the tumor necrosis factor alpha gene confers phorbol ester responsiveness to upstream transcriptional activators.

1992 ◽  
Vol 12 (3) ◽  
pp. 1352-1356 ◽  
Author(s):  
D C Leitman ◽  
E R Mackow ◽  
T Williams ◽  
J D Baxter ◽  
B L West
Keyword(s):  
Transcription Factors ◽  
Tumor Necrosis Factor ◽  
Promoter Region ◽  
Tumor Necrosis ◽  
Core Promoter ◽  
Core Promoter Region ◽  
Necrosis Factor Alpha ◽  
The Core ◽  
Factor Alpha ◽  
Necrosis Factor

Activators of protein kinase C, such as 12-O-tetradecanoylphorbol 13-acetate (TPA), are known to regulate the expression of many genes, including the tumor necrosis factor alpha (TNF) gene, by affecting the level or activity of upstream transcription factors. To investigate the mechanism whereby TPA activates the TNF promoter, a series of 5'-deletion mutants of the human TNF promoter linked to chloramphenicol acetyltransferase was transfected into U937 human promonocytic cells. TPA produced a 7- to 11-fold activation of all TNF promoters tested, even those promoters truncated to contain only the core promoter with no upstream enhancer elements. The proximal TNF promoter containing only 28 nucleotides upstream and 10 nucleotides downstream of the RNA start site confers TPA activation to a variety of unrelated upstream enhancer elements and transcription factors, including Sp1, CTF/NF1, cyclic AMP-response element, GAL-E1a, and GAL-VP16. The level of activation by TPA depends on the TATA box structure, since the TPA response is greater in promoters containing the sequence TATAAA than in those containing TATTAA or TATTTA. These findings suggest that the core promoter region is a target for gene regulation by second-messenger pathways.

scholarly journals The decapentaplegic core promoter region plays an integral role in the spatial control of transcription.

1995 ◽  
Vol 15 (7) ◽  
pp. 3960-3968 ◽  
Author(s):  
D H Schwyter ◽  
J D Huang ◽  
T Dubnicoff ◽  
A J Courey
Keyword(s):  
Expression Pattern ◽  
Phase Ii ◽  
Promoter Region ◽  
Core Promoter ◽  
Critical Role ◽  
Regulatory Elements ◽  
Drosophila Embryo ◽  
Phase Iii ◽  
Core Promoter Region ◽  
Flanking Region

The Drosophila melanogaster decapentaplegic (dpp) gene encodes a transforming growth factor beta-related cell signaling molecule that plays a critical role in dorsal/ventral pattern formation. The dpp expression pattern in the Drosophila embryo is dynamic, consisting of three phases. Phase I, in which dpp is expressed in a broad dorsal domain, depends on elements in the dpp second intron that interact with the Dorsal transcription factor to repress transcription ventrally. In contrast, phases II and III, in which dpp is expressed first in broad longitudinal stripes (phase II) and subsequently in narrow longitudinal stripes (phase III), depend on multiple independent elements in the dpp 5'-flanking region. Several aspects of the normal dpp expression pattern appear to depend on the unique properties of the dpp core promoter. For example, this core promoter (extending from -22 to +6) is able to direct a phase II expression pattern in the absence of additional upstream or downstream regulatory elements. In addition, a ventral-specific enhancer in the dpp 5'-flanking region that binds the Dorsal factor activates the heterologous hsp70 core promoter but not the dpp core promoter. Thus, the dpp core promoter region may contribute to spatially regulated transcription both by interacting directly with spatially restricted activators and by modifying the activity of proteins bound to enhancer elements.

The orphan nuclear receptor NGFI-B regulates expression of the gene encoding steroid 21-hydroxylase

1993 ◽  
Vol 13 (2) ◽  
pp. 861-868
Author(s):  
T E Wilson ◽  
A R Mouw ◽  
C A Weaver ◽  
J Milbrandt ◽  
K L Parker
Keyword(s):  
Nuclear Receptor ◽  
Transcriptional Activation ◽  
Core Promoter ◽  
Orphan Nuclear Receptor ◽  
Recognition Sequence ◽  
Mobility Shift ◽  
Adrenocortical Cells ◽  
Gene Encoding ◽  
Adult Rat ◽  
Gel Mobility Shift

As part of its trophic action to maintain the steroidogenic capacity of adrenocortical cells, corticotropin (ACTH) increases the transcription of the cytochrome P-450 steroid hydroxylase genes, including the gene encoding steroid 21-hydroxylase (21-OHase). We previously identified several promoter elements that regulate 21-OHase gene expression in mouse Y1 adrenocortical tumor cells. One of these elements, located at nucleotide -65, closely resembles the recognition sequence of the orphan nuclear receptor NGFI-B, suggesting that NGFI-B regulates this essential steroidogenic enzyme. To explore this possibility, we first used in situ hybridization to demonstrate high levels of NGFI-B transcripts in the adrenal cortex of the adult rat. In cultured mouse Y1 adrenocortical cells, treatment with ACTH, the major regulator of 21-OHase transcription, rapidly increased NGFI-B expression. Gel mobility shift and DNase I footprinting experiments showed that recombinantly expressed NGFI-B interacts specifically with the 21-OHase -65 element and identified one complex formed by Y1 extracts and the 21-OHase -65 element that contains NGFI-B. Expression of NGFI-B significantly augmented the activity of the intact 21-OHase promoter, while mutations of the -65 element that abolish NGFI-B binding markedly diminished NGFI-B-mediated transcriptional activation. Specific mutations of NGFI-B shown previously to impair either DNA binding or transcriptional activation diminished the effect of NGFI-B coexpression on 21-OHase expression. Finally, an oligonucleotide containing the NGFI-B response element conferred ACTH response to a core promoter from the prolactin gene, showing that this element is sufficient for ACTH induction. Collectively, these results identify a cellular promoter element that is regulated by NGFI-B and implicate NGFI-B in the transcriptional induction of 21-OHase by ACTH.

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